There is one more 'magic' option, depending on how much time you spend in the US.... If you have legal status (even a non resident alien work visa, eg L1 etc), and you have an address that sends you bills in your name.
You may comply with the personal import scheme.
Go to this page:
http://www.dotars.gov.au/roads/safet...ting.aspx#5.06
Scroll down to the eligibility section, then click on 'Personal Imports"
I haven't read this in detail for a while, but if you are in the US for a significant chunk of the year, you could be eligible.
I know that I would do this if the travel stars aligned.
Regards
Cameron