Some of the cost is probably due to the old "economy of scale". Sellers in the US can order them from the manufacturer's warehouse and get it in a few days, whereas here they could order them in bulk (aka Extravision importer), but have to pay for them up front. They may then sit on the shelf for months waiting for someone to buy one. There are so many different models the logistics of what to order must be horrific.
The market in the US is much bigger than out here so they may sell a CGE every week, whilst they may only sell a handful a year out here
I was able to get my CGE1100 within a couple of days because they inadvertantly ordered 2 rather than one. The "spare" one sat there for some time before I happened to order it! Otherwise, it could still be sitting there. If they order it specially, it would be very expensive to get out here. Have you enquired about the shipping costs from OPT to Australia?