Okay one last attempt at this

Get a empeg and a extra sledge. Then with the sledge weld two threaded bosses to the sides of the sledge similar to what you have on a CB radio so you can have a bolt going into either side of the sledge. Now get a CB mounting bracket (big wide U shaped things) and mount the sledge in this.

Now screw this to the top of your dash with some small short screws or glue it. Then you have a nice place for the empeg for sliding in and out. Run the cables for it up through the front of the dash through an AC vent for the screen maybe.

When you get out of car pull the empeg and you have an empty cage sat on the top of the dash. Crap for brains thieve looks in window and sees an empty sledge and things damn no CB in this car to steal.

When you sell car you will have some small holes in the top of the dash which is hardly going to have a major impact on the value of a 8 year old SUV with more miles on it than the space shuttle.

Or another way of tackiling it would be to pull out the glove box and stick it in the cupboard at home, pull out the AC vent in the way and place that in cupboard. get some duct tape and cover up the end of the duct ( and marvel at using duct tape on a duct for once). Get a piece of MDF and cut it so it fits into the hole left by glovebox then mount the empeg into this piece of wood and if you ain't got enough depth pack it out the way. When it comes to sell the thing remve piece of MDF and replce bits sitting in cupboard.

You are wanting a tool a way to make your life easier and more pleasant you aren't making a show and shine install so it doesn't have to be sexy.

Have you considered A karma and the sticking its dock to the top of the dash?