I don't know. Not unless a Blu-Ray player is being developed...which is a pretty strong possibility at this point...and to answer your doubts, MGS2: Substance was the only MGS to ever appear on the Xbox platform(s). And unfortunately, I don't like it nearly as much as I do the PS2 version. I'd have loved to play it on a 360 pad, though.
I don't know if MS is getting a port of it. It's tough to say that it will or even theoretically could, what with there being one previously planned for MGS3 and it never showing up - for starters. But I guess it's possible, however highly unlikely.