Here is my project from last year. This is actually my 2nd "truckputer", the first one was waaay back in 1987. I wanted to keep it simple and get the most bang for my buck. I also wanted to go back to stock pretty easily. This replaces the stock ashtray in my F-150, there was quite a bit of room for the PC behind it.
System Specs:
Intel mini-itx w/ 1.6GHz Atom 512MB RAM
80GB PATA HDD(pull from 4yr old dead laptop)
Crystalfontz CFA635 LCD
USB WiFi adapter
Ubuntu 8.10 Server OS
M3-ATX power supply
Custom enclosure
Features/Software:
Custom UI for LCD: Frontend for mpg123, asterisk, and wifi
OpenVPN to home network over WiFi
Asterisk for VoIP
Aircrack-ng
Construction/Install Pics

MB and templates for mounting and faceplate.

Fiberglass mold for LCD faceplate.

Faceplate out of mold.

Case assembly (mostly fiberglass)

Faceplate assembly (contains LCD, mic, power switch and HDD LED)

Finished faceplate, layup of 1 ply of carbon fiber just to try to match the OEM faux CF interior trim.

Finished case assembly

Completed, ready to install

Enclosure - rear

FM Modulator for audio thru factory stereo

Enclosure installed

Completed installation