Sounds like a cool idea but drilling holes in a car window can't be done. The glass is tempered (safety Glass) which means even if you use a diamond bit as soon as you turned on the drill the glass would shatter in to the little ice cubes you see at car accident sites. To put a hole in glass you have to drill it first then temper it. Once it's tempered as soon as you break the surface it shatters. Maybe gluing the hinge on like a rear view mirror might work.