In this weeks UK Sunday Times Magazine interview of King by Neil Gaiman, King hints he may take himself out of future drafts of Dark Tower 5 and 6.
Stephen King is a character in the fifth and sixth Dark Tower books, and Stephen King the non-fictional author is wondering whether to take him out on the next draft.
The books would have to be significantly changed for this to work. Sounds like a bad idea to me.
The whole article is here.