So I recently came across this Sony head unit that uses your phone as the display. http://www.crutchfield.com/S-R5Yo7jf...-XSP-N1BT.html
I thought it was clever, but why doesn't anyone make a unit that takes tablets? There are people who mod Android tablets and Ipads into their dash, so there's a demand for it. Doing some research, looks like a company named Paragon had a prototype device that never came to market. I'm surprised no other company has made an attempt.
Demo of this head unit: