This app was mentioned in 1 comment, with an average of 2.00 upvotes
Heh, I was looking more for the specific case OP was trying to achieve. I'm well aware of the idea, I put an LTE Nexus 7 in my dash. =P
For me the solution was to not even worry about the faceplate and rather to just use a head unit that has an Android app controller which lets me control the head unit from the tablet.