OK, after a long chat with my local RV guy about options he told me there was an add-on receiver that adds the 2nd receiver to a stock receiver and allows the use of a supertruss. However, he also said that he's done lots of them himself by welding an additional receiver under the original basically making a superhitch out of the OEM hitch. His take on it is and was that 'it's all just steel' -- of course the guy is a racer and builds race boats and cars too so perhaps that's just the way he thinks.
We discussed the Curt 2 1/2" receiver with single tube 34" extension and turn buckles as an option but again, he felt that really wasn't much better than a single 2" with a single tube extension and advised that making my oem hitch have two receivers to fit the Torklift SuperTruss would work better than the curt but perhaps not quite as good as the Torklift superhitch (non-magnum).
In the end, I'm having him add the 2nd receiver to my OEM hitch and some chain eyes for the turnbuckles and chains and then will use the 36" Supertruss extension. It should be good for what I'm doing since the single 34" Curt extension on a 2 1/2" receiver is more than enough for what I need.
Cost savings is about $300 but I think it's the way to go.