The intel chipsets will do it, but they require an odd driver from the intel site followed by the addition of some registry entries. Powerstrip isn't required. The only drawback is that it will be locked at 800x480 and will most likely only display on the Xenarc and not the laptop screen.

Somebody posted some really good directions along with the registry entries a while ago. He used a different Intel chipset than I did, but it worked for me with a little tweaking. Search for either "super 800x480" or "intel 800x480" or something along those lines. It was a long thread if I remember right.