How's this for an option?
The 211 E-class is available with solar panels built into the sunroof/wind deflector. They provide power to the climate control blower motor when the car is off. The blower motor runs at low speed to draw outside air into the cabin to keep the interior temperature down. Anyone who has ever gotten into a black/black car, that's been parked on a blacktop lot on a hot sunny day should appreciate this. We'll have to wait and see how effective it is.