I would very much like to see a Fallen Legends book.
I'll second this one, but mainly because I want to see stats on The Captain.
Cthulhu eats 1d4 players per round... No, wait, wrong game. As much as I would love, love, love to see a
Street Legends style book to cover the fallen heroes and villains of yesteryear, update the old timers for the new decade, or just teach these young `uns today with their ork`n`roll and conservativ ehaircuts just how aweseom Ghost, Dodger, and Sally were putting stats to some of these guys runs into the old adage in tabletop RPGs, handed down from one GM to the next like a well-worn set of dice: "If you stat it, they will kill it."
On a tangental note, I've long wanted to put together a "yesteryear" sort of book, that would let people use the 4th Edition ruleset for a game set in the original 2050s era. With cyberdecks, cd-roms, and mohawks... elf synthpop soundtrack sold seperately.