John Byrne has begun writing and drawing a continuation of his iconic X-Men run, picking up from the end of Uncanny X-Men #136 in a alt-history take on the franchise.
"Just had one of my wilder ideas. Remember when Chris was doing X-Men Forever, picking up from when he left the book? Immediately some people started speculating about me doing the same, X-Men Evermor, picking up from my own exit point," Byrne wrote on his forum. "But just now I thought of something that would be even more fun. For the sake of reference, let's call it X-Men Elsewhen, picking up with the coda of X-Men #136, but proceeding as if Shooter hadn't thrown his king-sized monkey wrench into the works! So Jean* doesn't die, Scott doesn't leave, and, well, a whole bunch of other stuff does and doesn't happen.
"(And, no, not scripted by Chris!!)," Byrne adds. "Never gonna happen, but fun to think about."
Byrne has gone on to draw eight pages for X-Men Elsewhen, adding in dialogue as well. Here is Byrne's running thread of pages from the project: http://www.byrnerobotics.com/forum/forum_posts.asp?TID=53933&PN=1&totPosts=7
Marvel's Phoenix: The Untold Story in 1984 included Chris Claremont and Byrne's original intended ending to Uncanny X-Men #137 where Jean Grey/Dark Phoenix lived.
Byrne has not stated any plans to publish X-Men Elsewhen beyond on his fan forum.