There have been rumours that a game entitled "Sega vs. Capcom: Great Clash Generation" will be announced at Tokyo Game Show. Apparently this new DS game is being developed by Sega (Dimps) and supervised by Capcom. Previous Capcom "vs." titles have had the developer first in the name, such as "Capcom vs. SNK" and "SNK vs. Capcom". A PSP port would follow in the new year.
Sources from both companies have confirmed the existence of the game, which is said to utilise both fighting and RPG elements. Megaman and Sonic are set to feature in the game. There has been no official announcement yet, but one is expected sometime in the next week.