Microsoft would have to rewrite its policies to allow mods. So no, no mods on the 360 version. Sony is more open with the PS3 (compared to the 360), so potentially there could be PC to PS3 play, keyboard and mouse support, and mods.
Although I suspect mods will still have to be approved in some way for the PS3 since they're usually pretty buggy. Probably part of that Unreal engine optimization is a way to easily put mods on the PS3.