I've always supported mine for safety. Good thing too as one day in the storage yard someone back their construction trailer so the ladder on the top punched a whole in the front of the cab-over and knocked it back enough to bend two jacks and rip one of them off the rear corner. If it had not been sitting on the trailer which moved with it, it would have fallen and taken out a nice bass boat and utility trailer with it.
I've used several methods over the years. One was four stacks of 4 cement blocks with cross boards. One was cross boards across a 5x8 utility trailer. One was a set of heavy duty sawhorses I custom made. Each had their own pros and cons but all stored the camper at truck bed height. This was important since I have manual jacks so minimal jacking was wanted.
