Much as I detest pain, it is generally a very useful thing — like fear. Whenever you see a “No Fear” sticker or tee-shirt, remember to mentally translate it to “No Brains”.
An Osborne Park company has had a look at the Lappyvator and is interested in making something like it for themselves. It turns out that the owner has back problems as well, and he showed me a nifty little sit-in device which looks like a padded plank swing with a separate back and a pair of stirrups, which also does good things for one’s spine. The “plank” goes under your legs, the back (attached to some rings on the straps supporting the seat) rides up on your back, and one foot goes into each stirrip, which are separately attached to the bar the whole thing hangs from and strapped to limit their distance form one another.