I've been keen on doing a carputer of sorts myself, but again, alas, with MN temp ranges, I fear it would fry most all the off the shelf stuff. The other issue is visability. I have a stack of old Crackberrys that have ideal screens for the environment (work in direct sunlight) But the units themselves are not really hackable (old OS/ can't get at any of the I/O) Have not seen anything on using the screens either.
I figured I would just start with the wireless entry via bluetooth and work up from there. There is a cut off point when there is more hardware in the car than the vehicle itself is worth.
"The right to be heard does not automatically include the right to be taken seriously."
-- Hubert H. Humphrey