The smallest fastest PC?

http://www.ipoxtech.com/ADE-6040.php

You can stick a core 2 duo in there and an x16 PCIe video card. I'm not sure how much it is though. This next one is $300, using the previous generation Intel chipset (doesn't support DDR2 800 ram):

http://www.commell.com.tw/product/SBC/LV-677.HTM