A Dutch journalist took a snap of the Rocksteady Studios address plague, and then responded that they could talk about it 'in around a month'. The tweet was deleted.
However this is the Internet, and if you tweet it we'll keep it.snagged the exchange from Jan Meijroos, where he added he wasn't allowed to talk about it yet.
Meijroos replied: "over een klein maandje ..." when someone asked him about the image, which roughly means he 'can't talk about it for a month'. It's unclear if Rocksteady are actually working on a next-gen Batman, as they could have switched to another super hero, or something cape and cowl-less altogether.
In mid-March there's the Game Developers Conference 20141 in California, but at the end of March there's also Rezzed 2014 held at the NEC Birmingham. Perhaps we will get a little something next month.