What about a drop axle with air bags? deflate to load, air up to get out and ride down the road. I've thought about 3000 pound axles with 1000 pound springs and some sort of air ride assist. This would give you electric brakes but still a decent ride. I was also told at school to get an intertube mounted under the car and air it up some to get the weight off the suspension to help keep it from cycling so much. They said the trailer ride to and from the track can be harder then the actual track experience. Not sure on it, and have never put a temp gun or anything on the shocks after hauling anything, so take it as second hand knowledge.