The way I see it, it cannot be a game for Wii since UE3 doesn't suport Wii development.
I can't be the average PC/PS3/360 multiplat à la DMC4 or SFIV because Capcom already possesses a decent engine for it.
Most likely, I think they've licensed Unreal Engine 3 for the development of an MMO. UE3 has already been licensed for several MMO's, so I think that may be it.
It's the fad of today: Every big publisher is going to have a Big MMO for the cash-in.