1Up.com has an interview with Hideo Kojima, the man behind Metal Gear Solid, and in the interview he says that the Xbox 360 is up to par with the PS3 in graphics power for Metal Gear Solid, and saying very little would be different between a PS3 and Xbox 360 version.
1UP: It’s interesting that you think you could do this on 360, though.
HK: Maybe some nuance or a small details here and there might be different, but I feel that hardware is no longer a matter. I’m just talking about PS3, 360 and PC. Revolution is totally different, but there are really no differences among the other three.