Why not put a few of those little vents we have next to our driver doors in the back? Maybe just a larger scale version of them to get some airflow. They don't necessarily need to come off the roof, but having one under/behind the driver seat, by the passenger door and rear of the vehicle could get some airflow going as we drive. I'm sure there are optimal spots to put them, but the fact remains that there are ways to cool off the trucks without using AC. My concern is the temperature of the metal in the cargo area. I shouldn't be burning my arm/hand/leg when I select a package.