Amazon.com has a listing for a new hardcover entitled The Quotable Sandman. The page has no information on the book other than a release date of May 2001, which they’re probably not aware is Right Now.
I’ll post more info on this when I track it down.
Update: Thanks to the Lance “Squiddie” Smith, knower of all bookish things Gaiman (ok, I’m stretching) says:
It’s a small (roughly 5″ square) hardcover book which combines quotes from Sandman with various Sandman art. 94 pages. The art is from all over: comics, galleries, trading cards, posters and T-shirts. So nothing new. Even the writers biography is taken from Season of Mists, I think.
I think it was originally packaged with the Sandman mini bookends.