My Nexus 7 already travels with me and has great battery life. The nice high resolution screen coupled with the ton of customization and apps made it a no brainer to integrate into my car.
I ran into a problem immediately. Unless I wanted to be a tool and mount a 7 inch tablet to my windshield, I was going to have to custom make this solution.
I wanted to be able to keep the factory audio system and be able to use that system even if the Nexus 7 wasn't with me. Additionally, I didn't want to alter the dash in a way that I would need to replace parts in order to sell the car later.
I toyed with InstaMorph, which in its own right is an awesome product. I settled on painted lumber connecting straps from the local hardware store. They ran ~$1 each and I only needed to buy two as I could get 2 supports from each.
I cut the straps to size, bent them using a hammer and vice, then painted them with PlastiDip. Using strong Velcro, I attached them to the top and bottom of the factory head unit, then put the center dash piece back in place. I wish I would have taken more pictures during this process, but at the time I was thinking it would be merely a prototype. I may redo the straps in the future so that have a little cleaner look as it isn't as polished as I would like, but time will dictate that.
The tension level was just right and the screen of the Nexus 7 remained unobstructed. With the battery life and a Bluetooth link to the Belkin Bluetooth Hands Free Car Kit (Alternate: Kinivo), I am able to keep a clean look and not have to attach data and power cables every time I get in the car. I have a Verizon MiFi (Alternate: TMobile Hotspot) at the moment providing a data connection. The navigation app you see in the pictures is Waze.
Standing off the head unit prevent heat buildup
Room allowed for the volume knob
Looks good even at night
All in all it solved the immediate need and I haven't had to revisit the project at this time. If you have questions, please let me know.