Rear camera mounted inside and pointing out back window?

Thanks - interesting responses so far. Will look at the garmin set up and keep the Rain-X in mind.

@RetSgt7114 - I, too, like the idea of having the video feed always on to give me a real rear-view. If I do an exterior mount, I was planning to power it via the clearance lights so that the camera would be controlled by turning the parking lights on/off rather than solely when in reverse.