So I spotted a set of tail lights on a car today, which might be workable. And by that I mean a lot of work.
Mitsubishi Pajero tail lights;
I know, they look impossible to fit. But here's my radical idea. Don't mount them vertical, but horizontal. So either with the curvature facing down or up. But notice the other thing, they have an integrated vent! My way of thinking would be to mount them with the vent towards the top of the car, so as to provide another outlet of heat from the engine bay. Remember, heat moves upwards.
Wouldn't be legal here in Oz, as I believe the indicator has to be on the outer edge of the rear of the car (ie towards the corners), but you guys might be able to get away with it.
Probably not really a great choice, and they're pretty huge to boot. Just thought it was cool they had an integrated vent.