So it's been a year since my frame was repaired/reinforced and I just wanted to post a final follow up.....
The trailer handles better on the road and interior cargo doesn't shift like it used to. The trailer tracks straight and doesn't get blown around. It no longer feels like it is lumbering along behind as much as it is 'flowing' with the truck. The frame modifications made as much difference as swapping the axles; having the two jobs done literally translated into a 200% improvement in ride quality and handling; seat of the pants sure, but very noticeable nonetheless.
If you're not into welding additional cross-members into your frame I strongly urge anyone with one of these big units to look at MORryde's crossmember kit which basically does the same thing:
Performance Crossmembers by MORryde - MORryde Products
The way my trailer is now with the frame supports gussets, added crossmembers, and 7K axles..... this is how this trailer should have been built if it was truly intended to be a traveler. The factory build as far as I'm concerned is designed for seasonal use only, not a traveler.