Here there are some pics of my carputer; that's an Athlon 1400MHz ATX mounted on an Opel Corsa (Vauxhall). More specs:

case: wood & aluminium, handmade;
alimentation: 600W Inverter + 350W Pc ATX power supply, using a delay circuit to prevent inverter kill due to pc cue corrent;
alimentation: updated to an Opus 150W DC-DC, big efficency gain;
On the Motherboard: Athlon 1400MHz, down clocked to 1050 MHz for thermal security; 256 MB Ram
Devices: 3,5" HD 80 GB Maxtor IDE, 5" Optical drive combo (DVD reader, CD burner)
Cards: Sound Blaster PC 128 (ess1370), Matrox MGA G200 (prodly supported by DirectFB), Ethernet rtl8139
Input: ps/2 cable going under the passenger seat, usb2wireless remote control (it emulates a mouse)
Os: Slackware Linux 10.2 with tons of kernel/rc.d patches to reduce boot time

Carton model of the case Working with wood Assembling wood pieces
Ripped pc case on the wood case The same from behind The hd elastic tray (antishock)
Final positions; inverter and 12v battery The hd tray in place The same, from behind
Another view of final positions Card connections Moquette applied
Processor closeup Motherboard closeup Pieces..
Final (mounted) On the car Connecting power
Update: Opus 150W DC-DC package Update: another OPUS view Video: jumping hd tray

Many thanks for getting this crazy idea real to Daniel (the one on the photos) and Dario.