Aussie Internet prices are still well out of step with the United States, which is one reason why I'd be very surprised to see these HD movie downloads take off here any time soon. I sincerely hope this situation changes.
I will point out a great site about Australian ISP's, plans, and the driving forces behind them:
http://bc.whirlpool.net.au/
There are some interesting topics covered there, such as PIPE (which allows downloads that aren't counted towards your limit). Its also worth working out if your ISP provides an off-peak or no-limits time - my ISP turns off all limits between 2 and 4 AM. A couple of Automator scripts can take care of the rest. :-)