Warner Brothers has taken out some new domain name registrations:
A listing had appeared in game retailer websites for a game called Batman: Impostors for the PC, Xbox 360 and PlayStation 3, which would fit right in with The Red Hood and Hush, both of whom were vigilantes trying to usurp Batman's position in Gotham City.
If this is a new Batman game, it'll be interesting to see who else is involved. One obvious candidate is Jean-Paul Valley as Az-Bats (or even just as Azrael). Nightwing would have to be a participant, too, as Batman's supporter.