nGhost has an obd2 plugin:
http://www.youtube.com/watch?v=GbiMpJNHE24
I have yet to meet a person who has gotten carman to run on anything but the n8x0. You can get it to display on a desktop by tweaking the SDL code (turn off fullscreen, use software accelleration instead of hardware), but unless you know python and sdl, it's not easy. The hardest part will be connecting it to a bluetooth scantool, which I don't think anyone has accomplished.