Check this PC out.
http://www.shimafuji.co.jp/product/semc5701a01.html
http://www.shimafuji.co.jp/product/semc5701a01.html
As featured on Gizmodo, this little PC is just what you need if you are looking to create the ultimate portable classic arcade system. The little yellow cube houses a Linux powered PC with 64 MB RAM and a 266 Mghz processor. The unit is truly tiny measuring a little under 2 cubic inches. The bad news? It costs $1300! Yipes!