vinyl letters leave a "ghost" on aluminum after they are removed - no matter how carefully you get all of the glue off.
No reason it couldn't be done on the rear window though.
Matthew McConoughy has his wrapped for every movie he has to go out and promote! Now that's overkill. You might find a picture here of "Sahara" on the side of his 25.
Today is a gift, that's why they call it the present.