Just got my Xenarc 700TSV yesterday, and tried it out with my M10000 which is sitting in a Travla C134 case (no room for any video cards).
After trying all 3 suggested solutions (848x480, 800x600, and 1280x768), I've decided that for me 800x600 will work out ok... not great, but ok.
848x480 simply looks terrible, you really notice the horizontal pixel skipping.
1280x768 was actually kind of nice, but even after scaling up the icons and font, there are still plenty of apps/installers/etc, which will be really hard to read. Also, I don't like the waste of fill-rate (must be the programmer in me).
800x600 is squished, of course, but I guess I can use media-engine to play around with the aspect ratio (hopefully also for movie playback).
The via driver situation is a bit frustrating... all the hardware supports 800x480, so do their CE drivers, just not the XP drivers. It seems that you are able to get a glimpse at how good 800x480 'would' look (by having the 800x600 mode running at 60hz, which cuts off the top and bottom of the display).
Ayway, all this has probably already been discussed
