The TruckPuter project

The last few weeks or so, I've been kicking around the idea of putting a computer in my truck (called a carputer) so that I could have access to my gig's of music. Once I convinced myself it could be done... Wait, let me clarify. A guy I know down in Florida has already done one in his car, and showed me/'splained to me how he did it. That was the motivation I needed to get mine going.
So, I have a 94 Ford Ranger with 154 thousand miles on it, bought and paid for.
Why would I spiffy up that old truck you ask? Cuz I can :)
It runs GREAT and why not add a little fun to it.
The truck does not have the extended cab, so I am very limited on space and I don't believe I can just mount a computer case behind the seat. Not enough room...
After looking at some of the websites out there (google "carputer" and you'll find a bunch), I figured I'm either going to build a slim case to fit behind my seat, or somehow gut the middle armrest/cassette holder and fit it in there.
The next deal is the hardware. Typically people are putting the VIA motherboards in their car, but I'm worried that they wont have the OOMPH for the media applications I want.
I have an old P4 1.4Ghz PC that I'd like to use. I have to make sure that my power inverter will handle it, and that the switches they have available will handle it. (still researching that one)
I am thinking about removing the radio/cassette player and just put an amp between the Soundcard and power the speakers... that way I can purchase and "In Dash" touchscreen that will fit where the cassette was.

As this project begins, I plan on posting pics of my progress.
It will be a fairly slow deal, as I'm going to purchase the hardware little by little.
In the meantime I can start building out the case for the PC.
I'm going to find a pic of the truck to post up here for the "before" pic.