When y'all pull one rear axle does everything "unwind"? If the bolts come out and the axle stays in one place, there should be little problem with a hub. If it turns a good bit, or if the last bolt out is really in a bind, then there could be some problems.
I do not yet own a deuce, so I can't say for sure.
As far as running with one hub unlocked, there will actually be very little relative motion between the unlocked rear hub and its' respective axle. the only time there would be any real motion would be in a tight turn, or if you were crossing a pasture terrace and the unlocked axle took the weight of the truck and let the driving axle leave the ground. I have done that with trucks that had a drag (unpowered) rear tandem. I would imagine that the only time you would have the rear hub unlocked would be on the highway.
As for an axle support bearing: Depending on what the hub construction looks like, there might not be any problem. If one is necessary, I would probably make something that looks like a nylock nut that would thread onto the spindle. Instead of a nylon locking insert, there would be a bronze bushing. After all our discussions about the lack of relative motion at that point, I am beginning to think there might be no problem.
Only a trial will let us know for sure.
Spicergear, since you seem to put your rig through its paces pretty well, any thoughts on the strength of the Selectro hubs? I could not tell from your truck picture with the logs whether or not you use them.
Regards to all
Robert Miller