Another game was just announced for the Dreamcast. It's called July, an adventure title in much the same vein as D by development team Fortyfive. The game will be published by Sega, also by the end of 1998 (with new "end of 1998" titles being announced at this pace, we'll have plenty of games to ask for during the holidays!).
Fortyfive recently opened up a web site devoted to the game, which features July's radio dramas. Of course, if you don't know Japanese, you won't be able to follow it, and there aren't any screenshots as of yet.