I didn't want to create a permanent mount to the dash for a tablet...so, bending a drapery hook that locks into the cassette opening and hooks over the top of a 7" tablet (with a gel slip-on cover), with the tray lid up works as a temporary solution.

Now to see if a Motorola T605 will work.

Duct tape, drapery hooks, and binder clips --- all the hardware you'll ever need.