From there, it's simple.
Call up a friend/relative in Australia.
Have them go to an Optus store and buy the phone.
They go home, activate, create an iTunes store account with your name on it.
Next day, go to the Optus store and pay $80 to have it unlocked.
Then, send it to you with as many iTunes gift cards as you want/lots of account credit, plus the phone.
Start the phone up, set up your itunes with your new account from them, change the APN and voila!
So keen to hear if someone tries this, or I may be an early adopter depening on how much dosh I have at the end of the month :-D