If I recall correctly, there is a built-in XP environment in 7 where you can happily run anything in XP, while 7 is up in the background as the main OS.
If that is correct, and actually works, that means you should be sweet as even if SP and Win 7 don't mix.
I am waiting for a good while before I change up to 7, that's for sure.
I have run winmbt and winww2 on win 7 without the xp mode.
The only problem is that the colors and grafics in the menue-screens are mismatched but when I start a battle it runs fine.