Live on a thumb drive?

With USB drives of 128-256MB now commodities, is it possible to carry your: Internet Favorites, My Documents, Outlook .pst and Outlook settings on your keychain? The real question is whether its possible to either:

  • set the appropriate user directories to a drive that disappears when the flash drive is removed, or
  • use a utility to do this at the press of a button

Anyone know? I’m currently splitting my time between 6 computers and keeping “authoritative” files is kind of a hassle (the big deal, of course, is Outlook). And, anticipating the “Use Exchange” suggestion, I use my server-class machines to evaluate OS’s; I can’t dedicate one to be a W2K3 Server 24×7.