I just booked exactly what you're trying to do over the phone with Qantas the other day. It was simple and painless - simply called their standard phone reservations centre and got the ticket quoted out at NZ$9,411 all-in with the following routing, which is just under the 34,000 mile limit:

NAN-SYD-SIN-HKG-LHR-JFK-DFW-SFO-DFW-MEX-MIA-LAX-AKL-NAN.

Had to pick dates for all the flights, but as you can change these at any time for no cost it's not a problem.

I'm in Fiji at the moment and on my way through I asked the Qantas guys here if I could book a RTW in Fiji ex-Australia/NZ for the Fiji price but no can do. They did say however that they get a lot of Aussies and Kiwis booking their RTW's ex-Fiji, and some of them use that final sector 10-11 months later to get back to Fiji when they want to do their NEXT rtw.