As my previous post documented, I've experimented with localbitcoins.com. Following the arrest of two Miami men for trading on localbitcoins, I decided to seek legal advice on the sitation in Australia.
Online research led me to Nick Karagiannis of Kelly and Co, who was already familiar with Bitcoin: I guess it's a rare opportunity for excitement in financial regulatory circles! This set me back several thousand dollars (in fiat, unfortunately), but the result was reassuring.
They've released an excellent summary of the situation, derived from their research. I hope that helps other bitcoin users in Australia, and I'll post more in future should the legal situation change.