I'm working on this right now. I have my shop up and running, but it's basically a lightly modified "watch" theme. Which is fine because I don't need anything custom.
However I'm currently having to use flat rate shipping which is going to bite me in the bum eventually. So I'm looking to port over the Australia Post module from Zen (they are very similar).
I've got it to the point where the modules will activate, but they aren't working. Unfortunately, the logging in this application seems very poor, so I have no idea why it's not working.
Right now I'm unable to post to any of the 4.x forums, so finding it hard to get support. I'm also not sure how willing anyone will be to support me because it looks as though a module like this would be a paid-for module if it was released by OSC.
I'm planning to just release it for free when I get it working.