Two that I know of:-
ZaggSparq - $100 but closer to $150 by the time it is shipped to Australia. 6,000 mAh, 2 amps output, the same as the iPad charger. Requires US/AU adaptor, one more thing to forget to take with you.
Energizer XP8000 - Available in Australia for $180. 8,000 mAh but only 1 amp output just enough to keep the iPad going (I think) and maybe slowly recharge it.
I want this mainly so that I can continue to use the iPad when the battery gets low.
Any comments and alternative suggestions welcome.
PS no need to convert USD to AUD at the moment.