My current cameras are ~120-140 degrees, and the image is 4:3. On my 16:10 aspect ratio monitors, there is an option to stretch the image - and this "re-expands" the horizontal dimension so things are a bit more visible.
I've had video mirrors for about 5 years and counting.
I am hoping that Tesla can effect the change in the law about video mirrors. They want to use them on the Model X, and I'm sure the Model S's they built after that change will also have 'em. Which will lower both the frontal area and the Cd of the already excellent Model S.