well, if you decide to go the dual boot route after this some time in the future, i'm fairly certain you can always get the x64 version and slipstream sp3 to it using nlite or ryan vm integrator. that's a simple enough task
WIN 64 is SP2 only AFAIK. It is also WGA exempt so a VL will update fine. No genuine to check.. Other than that, just use any clean XP 32 bit SP3 install and simply do not enter a key on install. It will install and give 30 day to activate. You can then run the oembios changer tool. This gives you the option of using ANY XP disc and making it valid once you are done..The changer will install the oembios in the ocrrect order and location, then add the correct key..eazy peazy...
See the edit to my post..also stay away from the loaders if you can..accidents happen and I can make you a batch script to add the cert and serial if you reinstall win 7...