Mounting the computer
I bought an epia M-10000 for this project. I bought a power supply specifically made for mounting in cars. It completely powers off when the accessory power goes away so that your battery doesn't drain. I have a 512MB compact flash card for booting Debian GNU/Linux. The plan is to install the computer in the space behind the drivers seat. If I had got the Bose radio upgrade there would be a subwoofer back there, but as it stands there's just a plastic panel covering a 10" subwoofer shaped hole. There is a ton of space inside, but none of the surfaces are flat. It is a major pain trying to get your hands inside and push a screwdriver hard enough to get the self threading sheet metal screws to take hold. I have cuts an bruises all over my arms at the moment...
In the end I mounted it on the flatest place I could find--upside down on the ceiling. Odd, but hopefully too many bits wont fall out while the computer is running. I put some tinfoil on the bottom of the area to catch any bits that do fall out.