I predicted the 360 in this thread.
It's a long shot, that's for sure. All conventional knowledge points to the PS3, as it's the console the game was originally slated for, and the preorders are looking far better for the PS3.
However, I still think the 360 has a better shot than people have been led to believe. It all depends on how mainstream FF is, really. The more it is, the better shot the 360 has at equaling its sales. The PS3 had only sold about 5.4 million in the Americas before FFXIII was announced multi-platform.
I guess the advertising plays a role as well. If MS has their own exclusive advertising, it'd help quite a bit.
edit: I don't think comparisons like Tekken are any good - those games are simply too niche, a larger userbase doesn't effect sales too much. FFXIII may be different - there's never been a very large game in the Americas in which the PS3 version has outsold the 360. Batman was pretty big, but it had exclusive features, an advantage FFXIII PS3 will not have (I think). Note that Resident Evil and GTA was associated with the Playstation brand, yet the 360 versions handily outsold the PS3's.
I know FFXIII is more distinctively Japanese, it lacks guns and whatnot that seem to be the 360's top sellers, so it'll be tougher. Eh, we'll see.
