Good ideas. guys, keep 'em coming!
I don't have any room on the tongue, the storage box and tanks take up all the space. The rear bumper is pretty strong, I would just need to detach the sewer hose holder I have bolted to the top, at present. The thing I dislike about those bumper mount holders is that I would almost have to have a spare tire cover and besides the additional expense, I'm wary of their durability.
The Bal type underbelly carrier has some merit, I'll have to do some measuring and see if I can use something like that.
I'd be interested in other options if anyone knows one.