I found a place in the UK who sell surplus fire brigade stuff. They had the nice big low pressure air bags I think you are suggesting above, and I had gone there to have a look and probably buy one or two.
But, deflated they are huge. From memory about 18"x18"x4' each one plus the hoses and control box which together take up about the same space again. Inflated they end up at about 4'x4'x4', so just one needed under the front maybe but to self right which was my plan I'd need a pair, and I don't have the room.
So I bought two high pressure pads at about 24"x24"x1" empty, I'll have to chock them to get the height but they fit. And still pricey second hand.