If they base their work off the PS3 port then it shouldn't take them long at all (maybe 3 months). Of course that is assuming that they understand how the PS3 version works. I say the PS3 version because it doesn't use DX at all, it runs using at least OGL. So it should be the easiest to port from. Well that is also assuming that they are actually porting UE3 and not going to cop out and just run cider to translate calls.