While you are shopping around why not check out Craftbrewer at the top of the page (no affiliation) and PM Ross to see what the freight would be. I know there are AHB members (EDIT: In Victoria) who have bought from CB and I don't think the freight was too savage. They don't weigh much, it's all in the volume.
That is where I got mine from, and from memory the freight wasn't too bad, and it arrived
in a timely manner. So if none of those dealers have any, you can try them.
I ordered 4 kegs the other day Ross said to Perth it takes about 8 days.
Australia Post is the quickest for small items 3 - 4 days but I think to expensive for a urn.