What's wrong with a hard wire camera? Every wireless camera I've tried (granted I only tried a few priced under $100) is either plagued with interference, had very limited range or a weird delay. None of those problems with the hard wire.
On my dashboard, I have a Garmin Dezi RV760 in a "bean bag" mount, just sitting in the center of the dash.
To the right of the rear view mirror I have a Go Pro suction cup mount, for recording out the windshield, scenic drives and such.
I also have a gooseneck holder for a tablet, which provides auxiliary navigation, that's mounted to a passenger seat bolt and is in the central console area, not on the dash.