Robin,
How much of a hurry are you in? There's talk of a SA forum member* making a trip to Canberra to pick up a bike, and travelling via my place. I will have room for at least one bike on the way to the Nationals. Reckon that between the two of us, we'd be able to help you out a lot cheaper than a commercial operator.
Just a thought.
*Not Tony, not Freaky, not Leith.