What about "Put Your Hands Together," the O'Connor pastiche written by George Alec Effinger under the pseudonym "O. Niemand"?I knew people immediately would suggest other stories for the book, and I'm honored that you're the first, Ted. I haven't read the Effinger story (first published in Asimov's in 1988), but I see it's in Golden Gryphon's 2005 Effinger collection Live! From Planet Earth.
I'll pass along any suggestions, but my understanding is that Payseur & Schmidt is interested not in a comprehensive reprint anthology of O'Connor pastiches -- like Golden Gryphon's 1998 Eternal Lovecraft, for example -- but in a volume of a few thematically linked stories that then can be lovingly illustrated, packaged and supplemented.
Still, I'd be happy to compile here a list of stories and novels, of whatever genre, that pastiche or otherwise pay overt homage to O'Connor and her work -- as opposed to the much longer list of fictions that simply share some of her preoccupations and techniques (Walker Percy, Cormac McCarthy, Joe Lansdale, Elizabeth Massie, etc.).