I was looking up something else and came across a blurb that said that "the Planescape module that must not be named" was supposed to be followed up by one or more sequels that would restore some of the previous order of the product line; but that Planescape got cancelled before they were published.
Has anyone heard any rumors as to what Mr. Cook (or others) had intended for the sequels?
As far as I remember it was supposed to be a trilogy of adventures, nothing about how the factions would return. They also planned a book called Factions of Entropy, and Uncaged 2.