Walt, when I emailed RR and asked if there was a local dealer near me in NY they told me the closest dealer was Kartwarehouse USA. When I spoke with them about frame/axle size and pricing they stated the price is the same ( at that time) for either a 30 or 32mm frame and a 40 or 50 mm axle. Upgrading spindle size, wheel type, front hubs etc all came at a small price increase. And all of them are supposed to have the removable front torsion bar. Some of the sites do not have updated pics of them. Its funny how you said the 30/40mm combo is too light for Yamaha class, my local track is a tight, twisty, bumpy layout and the fastest Yamaha karts in SR pipe are all 28mm frame 40mm axle setups with 17mm spindle mount wheels. I ran a 32/50 last year with hub mount 25mm spindles with poor results, although I blame a portion of that on my driving skills lol. I just bought a 2008 Margay Limo 28/40 to run this season in Sr. Pipe.
I spoke with Kartwarehouse and they suggested I buy a 30/50 setup for my 13 year old to race Jr. Tag with and a 32/50 for me to race Sr.Tag. His thought was this way the only difference was frame size, all other parts were interchangeable. This would help keep the price down on parts inventory.
If you get one could you let me know what you think of it and how it works out? Ted Hamilton had one a while back and set the quality was very good, but he never raced it so he had no experience as to how it drove.