The only other thing you could do is have a swing arm for your tablet. Best option, that gets as close to your list of wants is running a single din radio is the spot CD players go in the up-model trucks. Move your climate controls to the spot about that. And then you can run the tablet in the space freed up. Just a thought, but it doesn't keep the double din...
Alternately, and I don't even know if this is possible,but push the double din back or build out the dash so you can mount a tablet in front of your double din radio. Then, when you need to, dismount the tablet to access the radio.