I might buy one of each (Home and Pro upgrades) anyway...I've got more than one pc around to use them on. I wouldn't think there would be a way to do it but thought I'd ask, heh. I'll probably just try it to see what happens...just for giggles.
In regard to the Vista Basic questions...Vista Basic doesn't count as anything, so an upgrade is not possible. Basically, Basic is less than XP, heh.