SUCCESS!!! I have accomplished a feat wanted by many, I am running two users on one PC--both with full support and no performance loss. I can't say however, that the two users are on the same Vista. Neither can I say it was free. The cost in the end was about 1/5 the cost of a new PC. I will post a separate thread in these forums with a detailed tutorial. In general, I ran an instance of vmWare with virtual vista, put that app on fullscreen to the second monitor, and then the fun part--usb connections.
Stay-tuned, it may be up by the end of the day!