I don't plan on duplicating my current screen.. i want chroot debian (like yours) and get completely rebuild an xorg.conf from scratch using something like:

https://help.ubuntu.com/community/USB2VGA

and hoping to produce a completely seperate full screen debian working station... we'll see how it goes when I have the money for all the parts.

But eventually my goal is to have a docking station be just 1 USB cord away . It won't duplicate the current screen.. although I guess if you do the vnc hack thing it might... but It'll be interesting how/if it works at all.