Potentially this could be very cool, depending on how much effort you want to put in. There are some nice 7in touchscreens available cheap from Xenarc, and windows software designed for this purpose is available. If you want to use another OS, it's a bit more work. Have you checked out www.mp3car.com for ideas? There are some awesome setups there, and lots of advice and tips. I was considering doing it in my previous car, but the present one doesn't really have enough room :-(