A sun visor install would be a little rough for the display extender. It's a little thick and heavy, unless you want to drive with the visor down all of the time. Plus there's that ribbon cable to hide. I must admit that a different cable connector on the display side could make the package smaller.

I like the idea of stashing it in the sunglasses holder located in the headliner console of some cars.

It kind of goes without saying, but I forgot to mention in an earlier post about dash mounting - please avoid any airbag locations. It would be dangerous to have a display shooting through the inside of your car.