What I've heard they have in the pipeline is Galactic Tank Force, White Water sequel, and Barry Oursler's last game - which I suppose *could* be Alice? I agree Alice in Wonderland is a solid theme. But if Barry's game isn't Alice then it seems like they have a significant pipeline of releases before they could get to another Riot collaboration.
I just really hope that American ups their game with art, animations, etc... as this is currently a weak point. I've read that Dennis Nordman's last couple of game designs never got released so I'm kind of feeling like he's got a bunch of good ideas saved up and could put out something really hot if given the chance and budget.
Anyway... we'll probably hear something at Texas Pinball in late March is my guess.