The LEGO Online store has been updated, and 21104 NASA Mars Science Laboratory Curiosity Rover is now available.
The Australian price is $49.99, compared to $29.99 US. When looking at a straight conversion of the US price (add 10% tax, convert to $AU) that is a markup of around $13. While not the most over the top markup it is higher than some of the other sets.
The set can be purchased from http://shop.lego.com/en-AU/NASA-Mars-Science-Laboratory-Curiosity-Rover-21104