Quote - Regarding a clean install of Win7 from WinXP, would installing another clean drive as the boot drive and keeping the original boot drive in the system help at all?
I always install my applications to another drive anyways so they are never on the boot drive. However, Windozs has a nasty habit of spreading configuration files all over the boot drive.
I already have 6 drives in my system so another is no big deal.

wdupre has a good solution... Me, I would do that route if I were you. Just make some room on one of your drives and use it.