Hey Mick
I've been making some enquiries about this just today and have hit a few brick walls so far.
TNT can Sea Freight 1 carton into Darwin from California for $530:00 AUD which is a bit steep but I was thinking afterwards that a few items sent together might be the way to go and then split up the freight which would make it better for everyone.
I'm going to give this DHL mob a try and see what they come up with and I think if we can get a consignment at least onto the East Coast of Oz somewhere, that might be the way to go.
I can get stuff up here into Darwin from Melb/Syd or Bris for about 60 bucks for something about that size and weight.
I'll keep you posted after I make a few more enquiries.
Mick
EDIT: DHL is out of the question. They only do Express Airfreight door to door.
$1116:73. NO THANKS

Maybe TNT might be worth thinking about and split the freight up.
I don't think that there's a much cheaper solution mate.