ollowing a discussion in March 2002 in a readers forum regarding the novel 'And on the Eight Day'  Dale Andrews tried his hand at writing a 'new' form of pastiche. It provides an epilogue to the existing story. Dale has been so kind allowing me to put it here. It comes, of course, with a spoiler warning so ... if you haven't read the original story look away now!
It eventually led to the writing of the pastiche "The Book Case" by Dale Andrews and Kurt Sercu. The story found it's way into EQMM (May 2007) and had an elderly Ellery Queen aiding Harry Burke to find the culprit. Ellery is called in since the victim is found amidst a collection of his books...

Maxwell E. Siegel's 'Once Upon a Crime' was written in 1951 but was publicized much later in 2007 (Old-time detection Issue N°16 ) it had all Ellery Queen characters (including JJMcC) reappearing and it had Ellery deciding to have, next to his own name,  three "non-existent names" on his plate glass of his office at 545 Fifth Avenue: Frederic Dannay, Manfred B. Lee and Barnaby Ross". Nikki reverted to being called Sheila Brent and Mrs. Ellery Queen appears to be Paula Paris! Lee wrote to Mr. Siegel that despite the story's merits:"... this is the one kind of story we simply may not consider. For the editor to glorify himself in his own publication is unthinkable, not to say poor business."

In the September/October 2009 edition EQMM published a prequel to The Book Case  by Dale C. Andrews, entitled "The Mad Hatter's Riddle." Set in 1975, Ellery is called to Hollywood to serve as an advisor on the NBC Ellery Queen series for the filming of "The Mad Tea Party" episode, which fans will remember was the only episode in the series based on an authentic Ellery Queen story. Unfortunately (no surprise!) things go very wrong on the set ...

"And you, El, are also looking fit. Still writing those convoluted whodunits?
No. I gave up writing detective stories about four years ago. I still edit the magazine. I guess it's my vineyard."

Ellery Queen's Mystery Magazine also put up a teaser on this page...where the story was excerpted. (Remark: we mirror the page for a limited time only).

David Marcum had a JJMcC moment when he wrote the introduction to "The Papers of Sherlock Holmes" (2011) in it he describes how he found Watson's notebook containing original untold Sherlock Holmes cases in his aunt's house! David told us he tried to write in Watson's traditional voice. Ellery is mentioned in a very small way at the end of the book, in one of those Untold Tales that Watson refers to but never actually writes. In this case, it is in reference to an investigation in which Ellery and the Inspector, along with several other of the Great Detectives, helped Holmes and Watson during a time they were in New York.

2013 welcomed another Dale C. Andrews pastiche in EQMM called Literally Dead and it involved a return to that New England town who's town square was in fact round... There we find Ellery investigating the mysterious death of a well known author. Wrightsville, a locked room and a dying message! What more could we ask for!

llery Queen is probably the only author who became the leading
character in a mystery pastiche. James Holding, who wrote the juveniles wrote a series of pastiches, estimable mysteries in their own right.  In these series King Danforth and Martin Leroy creators of the detective "Leroy King" solve crimes on their own during a round-the-world-tour. The titles of these stories evocated the early Queen-work. 

  The Norwegian Apple Mystery, November, 1960
  The African Fish Mystery,  April 1961
  The Italian Tile Mystery, September, 1961
  The Hong Kong Jewel Mystery, November, 1963.
  The Zanzibar Shirt Mystery, December, 1963.
  The Tahitian Powder Box Mystery,October, 1964.
  The Japanese Card Mystery, October, 1965.
  The New Zealand Bird Mystery, January, 1967
  The Philippine Key Mystery, February, 1968.
  The Borneo Snapshot Mystery, January, 1972.

Crippen and Landru announced in 2015 they would publish a unnamed collection of these stories.
The auteur-editor appeared even less disguised in two mysteries with a MWA background. Robert Arthur's "The 51st Sealed Room" (EQMM October 1951)  begins at an MWA meeting in New York, with a number of inside-jokes and comments of special interest to mystery authors and goes on to murder. There is mention of EQMM then annual contest. Also, someone who has come up with an idea for locked room story says:"...when Carr and Queen and the others upstairs read it, they'll wonder why they didn't think of it themselves."
Brett Halliday is another mystery writer anxious to give the impression that MWA gatherings lead to murder. His 1954 novel "She woke to Darkness" begins at the annual MWA murder award dinner. Narrator Halliday gets into serious trouble after picking up a girl there and is forced to call upon Mike Shayne for help. During the dinner, Frederic Dannay asks Halliday to write another story for the EQMM contest. Manfred Lee is also mentioned; he was forced to stay home because of illness in the family. This actually also resembles the plot from a Columbo-episode "Murder by the Book" . 

In Chapter 88 of his wonderful 1978 La Vie mode d'emploi (Life, a User's Manual, 1987) the modern French author Georges Perec imagines the career of an art critic named Charles-Albert Beyssandre forced by circumstances to write under various pen-names; among the eight which Perec cites are "Fred Dannay" and "M.B.Lee". (Maxwell Siegel 'The French Author Connection'  Old-Time Detection dec 2009)

llery Queen, editor of his mystery magazine wasn't spared. He plays a pivotal role in several short stories concerning stories submitted to the magazine. The earliest example might be found in Baynard Kendrick's article on true-crime articles "The Case of the Stuttering Sextant" (EQMM March 1947) which was introduced by Clayton Rawson in the style of a Queen story.

There is Rick Rubin's "The Man who hated Editors" (EQMM May 1960) The story about an unsuccessful writer who devises an unusual scheme to get even with the editors who have been turning his work down. One of those being "Emory Quinn Mystery Magazine"

Marge Jackson had a different idea along this line in "Dear Mr.Queen, editor" (EQMM April 1963) She tells of a story submitted by a mother of 4 children which discloses an actual murder as well as a possible future murder. EQ as very concerned editor tries to head off the second crime.

"The Clementine Caper" (EQMM, November 1956) by Larry Van Benthuysen also involves the matter of publication in EQMM. A suburban housewife, Alice, reads a newspaper item about a discovered corpse, and this becomes the basis for her speculation regarding murder, as well as the following conversation with her husband, George:

Alice: George, listen. Clementine was murdered, and I
       can prove it.
George: Do you want me to call Ellery Queen or do you
        think you can handle the caper yourself?
Alice: You think you're so funny... Maybe I will write
       this up and send it to EQMM and become rich and
       famous and divorce you.

Alice solves the crime, gets the story into EQMM and...doesn't divorce George...

James Holding did fit a foreign edition of EQMM into 'The Inquisitive Butcher of Nice' (EQMM, July 1963) wherein one of the characters says: "The police will be angry if we touch anything...they will no doubt look for finger prints, clues, signs of a struggle. Thus is always done in Ellery Queen's Mystery Magazine which I read each month."

It was Allen Lang who found the ultimate use for EQMM. His "The Trail of the Catfish" (EQMM January 1962) is about a detective Max Holloway whose job is tracking down those who steal library books. One one occasion he literally uses EQMM as a weapon.

Arthur Vidro had an EQ pastiche published for EQMM, somewhat unorthodox it appeared only online (Oct 2011) and not in a print publication. In this story we have a perfect collection of EQMM marred. Thomas Velie & Johnson appear in the story but the sleuthing in the story is done by journalist Mark Wayne Howard (Velie also calls him 'maestro'). Which was inevitable since Ellery Queen only appears as the cooperation between Dannay/Lee.

In the spring of 2013 Joe Goodrich had the short story 'Dear Mr.Queen' published in the MWA anthology The Mystery Box, edited by Brad Meltzer ... Joe already made 2012 a special year by editing Blood Relations: the selected letters of Ellery Queen 1947-1950
Dear Mr.Queen is a story about a 14-year-old boy in a small Minnesota town who writes mystery stories and sends them to EQMM. He gets an idea for a new story based on events in the neighborhood---events that culminate in an actual murder, and Art and Life begin to mirror each other in unexpected ways.

EQMM celebrates the magazine's 75th anniversary in 2016. The August 2016 issue holds Joseph Goodrich's story called "The Ten-Cent Murder" and features Fred Dannay as a sleuth. It is set in the early 1950s when Dashiell Hammett was teaching mystery writing at The Jefferson School of Social Science in Manhattan. Dannay was an occasional guest in Hammett's classroom. In the story there's been a murder at the school and Dannay is asked to solve it...It involves a dying clue, which is right up his alley.

On 8/31/16 EQMM's blog, Something is Going to Happen featured Arthur Vidro’s delightful, “The Mistake on the Cover of EQMM #1” In celebration of the magazine’s 75th anniversary, the story included a “Challenge to the Reader,” which EQMM editor Janet Hutchings then turned into a contest. Although several names are used only EQMM as such is a real reference. The story itself had many Easter Eggs, some of which are easy enough but some might surprise you. If you couldn't find them all the blog provided us not only the solution to the story but also with "Easter in the Autumn" by Josh Pachter. Josh waists no time pointing us to the basket of Easter Eggs.

More and more the name and work of Ellery Queen has become significant and influential. Which resulted in his name being lend to characters. For example in Margaret Austin's 'Introducing Ellery's Mom' (EQMM July 1962) we find one of the stories in which characters have been named after Ellery Queen.
As was the case with Josh Pachter's "E.Q.Griffin Earns his Name" (EQMM December 1968) and "E.Q. Griffen's Second Case" (EQMM May 1970). A third story about the Griffen family, "Sam Buried Caesar," (EQMM August 1971) focused on Ellery's brother Nero Wolfe Griffen.

Richard M.Gordon wrote a clever mystery parody of Thomas Gray' poem called "Ellery in a Country Churchyard" (EQMM, September 1964).

William Brittain wrote "The Man who Read Ellery Queen" (EQMM december 1965) about Arthur Mindy, an alert 80 year old who is admitted to an old age home with the one treasured possession - his complete collection of the Queen canon. He solves a crime at the home a la EQ by use of pure logic and is rewarded by the compliment of being told: 'Thank you, Mr. Queen".

References
"From..... tqcb" by Nils Hardin in Xenophile #14, June 1975
"The Misadventures from Ellery Queen" Jon L.Breen  EQMM Sep/Oct 2005