I'd like to contribute some info if the community finds it useful.
Protocol description can be found here http://papers.sae.org/970297/
and here US patent # US2002003781
In short, it's used for transmitting a number of not very important signals (doors open/closed, engine temp, electric load, etc) between numerous computers . Analyzing these signals is helpful when doing engine conversion (swap) in modern cars.
Currently, I got a Matlab script to decode data stream and run a quick statistics over it (delete duplicating packets , etc).
If there's some interest to the topic, I would post examples of captured stream, and corresponding exported binary file and my script's output