Abandoned Projects/Mr.X

From neilgaiman.info

"I'm doing some Mr.X stuff with Dave. We're doing three short stories now, which will be appearing as the back-ups for Mr.X 15-17. Another story by Dave and I will appear in A1 and then in colour as a back-up in Mr.X"

-Neil, Neil Gaiman Interviewed By Steve Whitaker, 1989

Although the Mr.X story for A1 appeared as Heartsprings And Watchstops and Dave McKean did a solo story for Mr.X #11, the other three short stories never appeared.