If I was still looking for a way to cover or coat my teardrop, I would probably use liquid ceramic. The salesman was over at the house last night, and he said he can coat the teardrop for somewhere between $200 and $500.
The stuff is like a really thick paint, but it doesn't peel like paint. And the best part. It has an R value of 24. WOW. Do you know how many inches of polystyrene I need to get an R value of 24? Probably 4 or 5 inches!!! With a coating like this I wouldn't even need to insulate my tear. I guess they also use this stuff on the bottom of the space shuttle!!!
They have a website if anyone wants to investigate further...
http://www.liquidceramic.com/features-benefits.htm
Mike...