As far as I know, no bus system exists on the early 8-series.
I have problems with my MID (display) and would like to integrate it in a carpc-project, so if you find any info I'm eager to read it.
What is the status of your CarPC? Any pictures available?
I'm only still in the planning phase.. I want a pc in the car, but don't want to damage the original car to much. Thinking of a VGA/TS in the dash, with a portable in the trunk. (I have a tabletPC)