I installed such a system (CarPC) in my Scion. But instead on using an in-dash display route, I chose to mount the screen between the front seats (out of a cupholder) to make the screen closer to my hand for easy touch screen operations. Many I can do without even looking.
It's also easier to pull out of the cupholder and sit in the back floorboard. No one even knows it's there...
mp3car.com is your friend, for sure.
