Bringing this thread back from the dead.
I ended up using a modified cell phone windshield mount i found at tjmaxx on clearance.
Sorry I don't have any pics before the process started.
I drilled three holes I the back and installed 3 high strength neodymium magnets.

You can kind of see them behind the covering I put over the unit.

I had an extra back plate from a mountek phone mount I installed on the back of my tablet cover.
I used 3m moulding tape on the plate.

Here it is installed, I don't have navigation so I have a small "ledge"that the tablet sits on.
But the magnet holds the majority of the weight.



Works very well and it's very easy to remove the tablet.
Tablet is an asus memo hd7.