My mother's 1999 Town Car is equipped with the heated, electrochromatic driver side mirror. When she got the car not long ago, the glass was rather dark, and had some strange scratch-like marks on it. Finally, it got to the point where she could barely see anything in it.
She asked me if I could find her a new mirror. There are lots of aftermarket mirror setups, but they would need to be painted to match the car. I have no hands-on experience with heated mirrors, so I wasn't sure if any old used mirror glass would work, and I couldn't find used ones online anyway.
What I ended up doing is ordering a custom cut mirror from http://www.automirrorglassonly.com/. The glass itself is made by Burco Inc, here in the good old USA. There are lots of different items available for different cars, but all Mom wanted was a mirror she could see out of. She didn't care if it was heated or not. So for he car I got the simple glass overlay.
All I had to do is clean the existing mirror, affix the four self stick pads to the new glass, and apply it to the original glass. It was a perfect fit, and you can hardly tell it isn't original. The directions state that the heated option will still work, though not as efficiently. Thankfully, as stated before, Mom doesn't care... So far, she is very happy with her mirror, and I am a hero.