I've heard great stuff about Line-X and Rhinoliner, but they are also super expensive. I've also heard good and but Herculiner. That being said, I lined my Jeep with Grizzly Grip. I love it, and it came out great. If you want I can take a picture of what it came out looking line. It's also taken my beatings, and mud, and more beating.
What about the heat? Did it keep it cooler or should you just use lizard skin or somethin heat resistant?