I know someone who put together a system around an ASUS A8N-SLI MB, 1 GB RAM, 1 GeForce 6800 (so far), 2x 75GB WD Raptor drives, and an Antec Neo Power. He stuck the whole thing in a Super LanBoy case. He replaced the stock 120mm fan with two Antec tri-cooler fans (with the 3-position fan speed switch).
Worked out rather well.
Only recommendation: replace the nylon carrying strap that comes with the case with a better one. The one that comes with the LanBoy is a pain to put on and use because there isn't a stiff piece of material underneath the carrying handle to give the whole strap rigidity. Other straps you can buy have that stiff piece of metal at the top of the strap where the handle attaches. That way the strap doesn't sag when you carry the system. Feels more secure that way. You can also get a shoulder strap.