Just got my new device and buttons in. Wired up the map button to power and we're ready to go. Just need to do some mounting. No line interference as is when it's sitting benchtop, but we'll see what happens when it gets inside the dash.
I opted to go with something besides the Nexus 7. It bothered me so much that the screen size window in the nav bezel was 6.51352324325463... inches so I went with a cheap chinese knock off. 6" screen and enough bezel to fill in the rest of the gap. At $150, I figured at worst I would have a new e-reader I can pass off to a family member when I got tired of it.
The processing power is leaving something to be desired, but it still does GPS, bluetooth and audio just fine. Tethering it to my phone is all I need. Aside from the damn time to show up in the gauge cluster