I'm surprised they don't offer some sort of padding between the case and your back. I can't imagine walking very far with the case rubbing against my spine. You could probably fashion some kind of pad on your own.
Marion- If I were interested in such a harness, I'd try to make one. I'd go really cheap, and use the shoulder straps from an old backpack or book bag, and a couple of pieces of rope or nylon strap to tie around the case. It sure would be ugly, and may not work as well, but I could make one right now for free.
At this time, the furthest I have to carry my instruments is from the truck to the center of the park, maybe 50 yards. More problematic are the amps. Hmmm. Do they make one for a bass amp? :)
But if I were planning very long or repeated trips, I'd probably spring for the real deal. It would probably be more comfortable in the long run, though I've never used one. And 40 bucks doesn't seem unreasonable to me, if you really intend to use it a lot.
Thanks for the post, Marion. It looks like a good idea, and I've never heard of it till now. BlueJay