John, our Citrix remote support software (GoToAssist) allows us to log onto remote Macs (i.e., not just PCs). Maybe we could troubleshoot this directly if Lee would grant us permission to log on to one of his iMacs both in BootCamp XP and Mac Leopard mode to explore the issue? Let me know if you guys are both into this and I'll help you get the session(s) set up.
Also, Lee, any chance you could try a Windows 7 install on one of these machines?