I was thinking about this the last little while, and I thought that it was a great idea. I also heard that drop coils are designed to lessen the rough ride (thought I read it in a magazine). So in the back, you would swap out the coils for 'bags, and then what? Would you have an onboard compressor?(expensive) or would you just have the air valves coming out somewhere and you can fill them wherever? How much weight can two bags in the rear hold? You could do the same with a half ton aswell right? Thats a good idea.