I think your best bet is AA - 62.5K miles for one-way Biz, North America -> Australia. You could do something like BOS-LAX on AA, then LAX-SYD on Qantas. However, you would have to look early. Since you have 30K miles, a 50K credit card offer would do the trick.

UA costs 67.5K miles, and you may be able to route via Asia. Air New Zealand can also work.

*Edited no-coffee typos.