Are you saying the RC can be upgraded using the $50 pre-order Win7 Premium Upgrade?
If so, this is the first I've heard of it. Sure, you can upgrade RC to RTM using cversion.ini edit, but how would the paid upgrade version verify XP/Vista license to proceed?
This would be a lot easier than putting XP or Vista back on in order to upgrade. Can anyone provide a link or confirm it is possible. And how would we know for sure now?
Supposedly the upgrades just seek a prior genuine version of Windows (and MS indicated at one point that includes the activated RC).
Such a check would look for (1) Minimum build -- formally XP, but it sounds like 2000 works as well, and (2) genuine status.
Anything other than a Vista build and it makes you fresh install.
The RC can't be re-activated forever if you install to a blank drive in the future, but it should work for now. MS supposedly isn't making people go back and fresh install Vista or XP to use the upgrade discs if they took their chances with the RC.