Coleman "Low Profile" rooftop units and Dometic Penguin and Penguin-2 units are ten inches high. Low profile roof top units may be the best I can do. Carrier had a low profile RV AC, but they quit the RV market.
Low Profile Air Conditioners on Sale - PPL Motor Homes
Sherwin Williams sells
paint that reflects 90% of the sun's energy back into space. I am going to buy a trailer with an aluminum roof and paint it. I specified a 90% reflective membrane roof for our sun room remodeling project a few years ago. I doubt that is what the RV makers are using for roofs. If they were using a cool roof, they would promote it.