Here's how to buy and sell .com.au domains with AUDA's blessing (This is based on my own observations and experiences) ...
Step 1 - Register any .com.au you want using the "close and substantial" rule, which considers domain monetisation to closely and substantially connect you with a domain. (All you need is your ABN)
Step 2 - Put some phoney baloney web site on it, so that you conform to this policy.
auDA > auDA Published Policies > Domain Monetisation Policy (2008-10)
In fact, you can skip step 2 altogether unless someone registers a complaint with AUDA. Then you can take your sweet time throwing some crap together, because AUDA don't exert themselves in pursuing these complaints anyway. (In my experience they make the person making the complaint feel like they're the one doing something wrong)
Step 3 - You solicit people who you think might be interested in buying the name. (I have had people call me offering to sell me .com.au domains in this manner)
Step 4 - If they are stupid/rich enough to pay the extortionist price that you are asking for it, you simply transfer legal ownership to them using this policy that enables you to transfer legal ownership of a domain "for any reason" -
auDA > auDA Published Policies > Transfers (Change of Registrant) Policy (2008-08)
Voila! You've bought and sold a .com.au for profit with AUDA's blessing.
The only small inconvenience is that you can't transfer legal ownership within 6 months of the initial registration. So you have to hang on to the name for a minimum of 6 months before transferring legal ownership.
So while AUDA have a written policy that says "You cannot register a domain name for the sole purpose of resale or transfer to a third party." They have other policies (both in writing and in practice) that are allowing thousands of .com.au names to be traded as commodities while companies with legitimate business uses for those domains have to settle for inferior alternatives.
I complain but nobody listens.