Originally Posted by Jayhovah

I did some research into this a while back when I considered ditching the stereo to go full tablet integration... The Nexus 7 is the tablet to have for something like this because someone created a custom ROM for it that will allow the USB port to power/charge the tablet while also functioning as a USB host for accessories. With most other tablets you will find this to be an annoying barrier to tablet integration (you either get to power/charge the tablet or connect USB accessories, but not both). You could then use the USB host capability to integrate buttons (or even interface to your steering wheel buttons!), cameras, OBDII, external sensors, etc etc etc.

For something like this, it would probably be perfect. For completely replacing the stereo, I did not think it would be viable for two reasons:
1) Bluetooth calling - the tab can not connect to a phone to act as a hands-free device for calling... which sucks because it has all the necessary hardware (bluetooth transceiver, audio out jack, integrated microphone) . It's a limitation within android at the moment.
2) The custom ROM was only made for the Nexus 7, and I wanted to replace both the stereo and cubby with a 10" tablet.

Hope that knowledge dump helps someone.