Not easily grabbed from a junk yard like Lincoln bags...and not even really that easy to use but...
I was going to use these bags from Mercedes Benz R-Class. They are rear bags. The R-Class can tow 4000 lbs. and payload 500 so, they're pretty tuff. I got these because they were pulled for leaking down when the R's are parked. Band clamp at the top of the bag leaks a bit. For me, "falls down overnight?... Whatever..."
I was going to try and make them work (and still may...) but for the foreseeable future I'll be rolling static.
This is fully compressed...
...Full inflated height...
...the air line inlet and the top...
And the bottom, which is a little weird. You can see how you could position it to work, or you could grind it flat. There are no threaded holes to bolt them in with though..
I don't think you could ride them deflated. The plastic ends would just hit until they broke.
You could hit up a local Benz dealer who throws these things into the scrap dumpster (ask first!) and even ask if they would set aside a few for you.
I have about 4 or 5 of them and anyone would be welcome to them if they like.
Just an idea.