Happy to pay shipping to Australia.
Looks like you can get a complete rebuilt one in Aus for $1600https://www.ebay.com.au/itm/Toyota-supra-w55-w58-gearbox-fitted-with-new-bearings-synchros-and-seals/233541495677?hash=item3660286b7d:g:wEwAAOSw3SdeEmlP
Best of luck on your search mate! W58s are in really high demand right now... believe me. I'll keep an eye out.