Cavalier overhead screen mount possible?

My sis wants video in her 2002 cavalier.  For obvious reasons I suggested she get screens mounted in the visors but she insists on having an overhead mount screen.  The only place to mount it in such a small car and have a halfway decent viewing angle would be right behing the rearview mirror.  I've never worked with video before but ive done tons of audio so im somewhat literate on the sort of thing, I'd just like to know if it's even possible before she buys a screen and i go tearing her car apart. 

Thanks a lot for your advice.  I ran the idea by her and the glove box seems out of the question because it HAS to be viewable from the driver's seat.  It seems she has a death wish.  Also she can't stand the thought of having her vanity mirrors removed from the visor.  Any other possibilities?