I'd like an earth-one Batman. It would be a great way to flesh out the new world with new takes on all the villians and supporting characters. It would be great to actually tie the game to the comics in a similar way that was done with Ultimate Spider-Man.
I totally just got that that suit was from the Geoff Johns / Gary Frank graphic novel. I've been wondering where they got that suit design for forever and a half at this point.
I think, from a game design perspective, Sinestro Batman wouldn't really work. The cool things about the Lantern Rings (I totally did that on purpose :P) is that fact that they can make anything the wearer wants, which is impossible to do in a video game. Granted, you can contextualize it in the story by explaining these are the things that Batman would make with one of these rings, but ultimately, the constructs would just replace the gadgets and you'd get a game that was very similar to the last.
Batman Beyond could be pretty cool because you'd get a whole new aesthetic with Neo Gotham. They'd have to give that game a completely different look, which would be rad. Combine that with the different things the Beyond suit can do and the different way that Terry would handle himself in a fight and you've got a pretty good formula for a game, I think.
Batman: Year One and The Dark Knight Returns could be cool as well if for no other reason than the fact that Bruce wouldn't have the support staff that he has in the current games, so he'd have to do a whole lot more on his own. It'd make the games feel way more solitary.