Breaking news out of Capcom's TGS press event happening right now, Inafune just announced Dead Rising 2 "Case West", which serves as the epilogue to Case Zero's prologue status. It will take place after the events of Dead Rising 2 and will feature both Frank West and Chuck. This epilogue is exclusive to the Xbox 360 too according to Inafune.
On a somewhat unrelated note, Capcom has apparently purchased Blue Castle studio's now and it'll serve as Capcom's Vancouver studio now.
*** Update 2 ***
The teaser trailer for Case West can now be seen at this link. The official website has also gone up here.
*** End Update 2 ***