Capcom has announced that Dead Rising 3 is in the works. Here is the quote:

"Obviously, with all of that success on Dead Rising 2, it makes sense to move onto Dead Rising 3," said Reeves. "I think that they [developer Blue Castle Games] may extend it by bringing in new characters and new interactions, or bring back others from before.

"The idea would be that we'll bring digital content to bridge a link between DR2 and DR3. It's a bit like an online game in that way - a continuous story. I don't want to say episodic, but I think you'll be find there'll be scriptwriters coming in to [continue the story]."