Wow.... no-ones mentioned a Pico ITX yet... strange indeed!

Basicly, its just a small motherboard. Comes with everything you need for a car setup IMO, but dont even think about playing games on it.
(Note: Wasnt ever sold with the six channel sound card)

see here: http://www.mini-itx.com/reviews/pico-itx/

Other option if you have more room... go the Mini-ITX boards.... They are the shiznit!

See: http://www.via.com.tw/en/initiatives...itx/car-pc.jsp

They will all require you to have some basic computer knowledge tosetup... but the rewards are immense :P. Having the comp boot up on accessories switch, having it shut down the rightway everytime you turn off your car (small battery) and the fact that you can stick it anywhere!!! 12x7.5cm.... quite small indeed! (can go smaller... but abit more $$$)