Alright, as I gather my thoughts for how I do this install, here is where I'm currently at.
I will be eliminating the need for a headunit altogether, and fiberglassing my Nexus 7 into the dash. A Clarion EQS746 will be mounted behind the dash, with an RCA level controller mounted in my dash for volume. The main input on the EQ will be a bluetooth module, connecting to the N7. I don't have room for the EQ to be in the dash, which is why it will be behind it.
I will be creating my own POGO pin charger, to keep the tablet charged. I will also be integrating NFC tags into the dash, that will tell the tablet to automatically turn on BT, Wifi, and music.
In addition to installing the N7 in my dash, I will be creating a pod for my phone to sit in. Again, it will have POGO charging, and an NFC chip to automatically turn on Wifi Tethering.
This should be fun. I will be starting this within the next week or two, hopefully.