Back in February, some rumors were circulating the internet regarding a possible new Batman game, entitled Gotham City: Imposters. Now, just two months later, some evidence has been uncovered lending credence to the previous rumors.
Warner Bros. has registered the domain batmanimposters.com. The whois records for the domain are a perfect match for the domain of Warner's upcoming Batman: Arkham City.
Batman: Imposters (or Gotham City: Imposters) isn't yet official, but if Warner is registering a domain for the rumored game, there's a good chance we'll see something more concrete in the future.
Batman: Imposters is said to be a downloadable PSN or XBLA title. We'll have more information for you as it comes in.
Thanks, supererogatory