I have a question about your idea on micro ballons, if you mix with latex paint would it adhere good to the bottom of the car or would it be advisable to only use it on the inside of the vehicle? It seems like latex would not be a very good mix, I am no expert by a long shot but how would it hold up to heat say in the roof area, would there be any special prep on the body before painting it on or rolling? Would this mixture be close to the same as the lizard skin or coolcar? If it is that easy to produce why in the world would they charge so much for the stuff?
Sorry to ask all these questions, but your idea sounds great and I may do this when the time comes myself.