What was involved? A Raspberry PI (Model B Revision 2 - important for GPIO pin locations and hardware specifications), a "standard Car display from China" with two 2 video-in ports, an audio amplifier, an NF Filter, switches, wood (for the front panel) and wires...
There's also a 12V to 5V converter - "because the Rasbperry works with 5V and my car uses 12V, I bought some cheap converters from China for a cigar lighter and dissembled them for my purposes".
Check out the web page detailing his work - there are lots of pics, a video, and running commentary on the various problems and pitfalls he encountered. He also supplies links to download the source code, scripts to preconfigure your Linux, and the complete image (Part1, Part2, Part3) for a 4GB SD Card.
I put all parts together, installed a raspian image to a class 10 sd card and used VLC to tested if the sound and display came up. The first problem was that i had no sound. After some searching, i found the solution in changing the standard sound device of the raspi which should be "analog" for my project and not "digital". I will add every tutorial i used to change Linux at the end of this page, so you wont spent that much time i did for realizing this project.