Actually there are some computer cooling systems that you can get cheap that can be configured for use in R/C rigs with a little creativity. Once again any kind of cooling system that requires a power source is kind of counter productive. Heatsinking or conductive without power cooling is the key to keeping the temps down. If you have to add some kind of cooling device that draws power, that in itself creates more heat. There have been many discussions on this matter and some of the most knowledgable guys have logged in on this like BrianG, Lutach, and a few others. "KISS" or keep it simple stupid comes to mind (no offence intended). Try producing better heat sinking, and better airflow through your vehicle.