It seems that most of the concern is about objects in the center rear blind spot while backing up.
So...
I've got it!
A small fish-eye mirror similar to, but more stylish than, those on large step-vans.
Unlike the step-vans, you wouldn't want it in the wind all the time ruining the aerodynamics.
Have it tuck into a molded indent cavity in the rear or roof area of body of the vehicle.
It could lay down flat and be flush with the body surface being no more conspicuous than the fuel door.
Of course EM would have to include this in the body molding.
Install a simple and inexpensive spring release and retrieve cable system.
Pull the trigger to "release" the mirror and it softly pops into position at full staff.
Have some sort of mechanism that will allow you to "reel in" and re-lock the cable in the "away" position.
Yep, somewhat similar to that picture of the VW mirror that someone posted.
EM is all into using existing but updated tech right?
It may sound a bit out there, but with the right effort, it could look good, work even better and cost very little.
Other than that VW, I've never seen it done before. Thinking outside the box right?