According to Variety, Rocksteady is working on a Batman: Arkham City prequel that's set in the Silver Age. It'll tell the story of how Batman first met The Joker, and will seemingly carry much of the 50s aesthetic with it, as opposed to the dark and modern take we've seen in previous games.
As part of DC Comics' new plans to "monetize" its superheroes, the story will also involve Batman joining the Justice League of America. Expect cameos from Superman, The Flash, and Green Lantern as DC tries to get us excited for some inevitable movie project.
I can't say the Silver Age holds too much appeal for me, but with Rocksteady kicking ass on the last two games, I'm definitely open to the idea.