I don't know if you got your answer but I got my two from Daleys nursery and they delivered!
www.daleysfruit.com.au
It was in the ornamentals section.
Good luck.

Every so often I end up on the Daleys website, and then I remember why I haven't bought anything from them: there's a min. (mail) order of $130 :-(

But if you're in Bris and don't mind a 2-hour drive, you can visit the nursery in person and collect the plant yourself. I see that Daleys is offering grafted M. albas, which jogs a faint memory about flower/scent quality being superior on grafted plants than on seedlings.

Before you make the trip though, you might try asking your local nursery. They almost certainly won't have it in stock but they can probably get it for you if you order it. Given the parlous state of the plant-nursery industry in the drought, they should be keen to find it for you and make a sale!

Incidentally, how is the Michelia doing in Shepparton? Aren't your winters quite frosty? Or hasn't the Michelia experienced its first Shep winter yet?

It has grown through 3 winters and is about 10 foot high now. It does go slightly brown in the cold but it's placed up against a north facing wall and so far has survived.....even the -6 degree frost of last week. In summer it goes green and flowers beautifully.

Three winters + 10 ft: you must be pleased! Gives me hope that my potted M. champaca might be able to survive the Ipswich winters in the ground so long as I can find a sheltered spot for it in the yard.