A magazine in the UK made one once, but I can't remember what board it was let alone the magazine's name!
I had a play with a VIA board a while back, and while they're not too bad you have to think of it as an old Cyrix chip (which basically it is), so the 800mhz chip will be more like 600-700 performance wise. You'll manage most 2d games, but I wouldn't try CHD games.
I'd get a socketed mini-itx board if you want to go down that route, it'll cost more but the performance difference will be worth it. Check out LinITX to get an idea and then get on google to find it cheaper.
http://linitx.com/viewcategory.php?catid=137&pp=137