I found this on a website whose name escapes me right now , but the content was too cool not to share, the author is mentioned below
By : Game Raging Psycho
Several sources reported today that Rocksteady, the studio behind Batman Arkham Asylum and Arkham City, are working on a prequel to both games featuring the JLA.
This prequel will involve Batman’s first battle with the Joker and his first encounter with the JLA members. It is also rumored that the game will have a stylized 50′s Silver Age feel. However some concept art from an artist who worked on the Arkham games popped up shortly after the game itself was revealed.
It’s unknown if this really is concept art from the game itself but considering the style of the characters themselves there is a very strong possibility that this maybe from the real game. As for the release date sources say 2014 at the earliest. This is a plan from DC to use video games like this, Lego Batman 2 DC Superheroes and Injustice Gods Among Us to build up hype and awareness for the team and movie through video games to non comic book fans.
Here is the rumored concept art for the game: