Well Samsung is the closest in the development of a
OLED display. This 'flexible' display is very thin. This would be The easiest to put in the car without much added weight, but it is still in the prototype phase. Samsung resently introduced a 40 inch (101.6 cm) diagonal Full-HD LCD TV panel only 10 mm thick. The full article is
here. I don't know how big a screen you are wanting to go, but I'm rather sure that they can make one to fit what you can imagine. I would suggest though that you look into a OLED display for your rear window idea.

They qualify for everything that you would need in that kind of application. Considering the flexible article is a few years old. It could be further along than the article suggests.
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Red Baron