I know everything automotive has been done before, but I haven't seen this one done.
Just glue an extra rearview mirror on your windshield.
If your car permits, glue it on your left side.
For you guys that are doing driver's side mirrors on the inside, you could make a bracket and mount a rearview mirror sideways (tall & skinny). F-14 Tomcats used 3 interior mirrors. I don't see why it wouldn't work on a car.
