Takeshi Horinouchi is the actual producer of the Megaman series right now, he is the man you WANT to go to for Megaman happenings, in last months issue of Nintendo Power. He said something very interesting, here is what it was:
NP: What's the next Megaman game on the horizon? More Star Force, ZX, or something else?
TH: This interview is coming out in January, right? [Close enough] Based on the timetable for the North American audience, I would assume the next game you get will be for the Star Force series. However, I'm sure you'd be happy if we got another game out to you before that.
What is interesting about this is that Star Force 2 does not have a release date, but has been heavily rumored to be released in March or April. Now he alludes that it is
possible for Megaman to appear in a game before that, however there is no game before that that he could possibly be in. Except one... Brawl!