I was thinking that a kool place to mount a screen would be under the passenger side airbag cover. Obviously, the bag would have to be removed in order to do this. But, it would be really easy to put a set of hinges on the rear of the cover and some type of small hydraulic lift to assist in opening it. I'm thinking some simple type of magnetic catch could keep it closed. Or maybe making it so a release switch or lever could be in the glovebox. That way it could be kept pretty stealth when not being used.
