I temporarily lifted mine so I could work under it. Just used a floor jack, lots of wood board pieces and some sturdy jack stands. After jacking about 8 inches, the stands were placed onto the reinforced area of the frame, near the axle. The TT was also hitched to the truck, with parking brake set and the tongue jack run out. After jacking, I ran out the stab jacks. The RV was super stable inside, after removing bounce from the suspension.
My rv frame didn't bend, and the world didn't end. Your idea sounds similar, I suppose the issue is - how do you balance the weight across six manual jacks, knowing the frame will not be tolerant of any miss-matches?