First one clarification:
These are torsion axles, I don't think you can make a leaf spring axle fit an rpod without major surgery. There are 5200 lb torsion axles available if you want to go that route, which would probably be the best solution in the long run. You would also need new brake assemblies, drums, wheels and tires for the 5200lb changeover, so that will get pretty spendy.
Yes, the inboard axle mounting points on the rPods do substantially increase the axle tube loads, actually by close to a factor of 2. That being said, it is worthwhile finding our for sure what is causing your negative camber before deciding on the fix. It could be the axle tube, but it could also be the spindle or the torsion arm. If its the tube your local shop might be able to straighten it but it will be weaker afterwards, if its one of the latter two problems your axle is probably toast.
Once you find out what has failed on your axle please post that and some photos on the forum, it will help others here troubleshoot their axle problems in the future.
If you determine its the axle tube and the shop is able to straighten it (it should probably end up with a little positive camber built in, I have about 3.8 inch in mine), you might want to look at the reinforcement mod i just did on my 179 last week. I posted a topic on it. I didn't want to extend the frame mounting points because that would put additional torsional load on the frame rails, which are pretty light (IIRC they're 0.1 inch wall thickness 2x4 tubes). My fix worked out well for the "diamond" axle tube I have, some rPods have round axle tubes which would be harder to add reinforcement to.
Alternatively, you could weld in a gusset plate between the torque tubes to help handle the torsional load on them from extending the mounting points.
If you go with a new axle you can get the mounting flanges wherever you want them, but probably with a 5200 lb axle you could leave them where they are and be fine.
Good luck, and welcome to the forum.
Edit: 3/8 inch camber not 3.8 inches