You can get industrial hardware like this one from McMaster Carr. You could also get "higher end" ones from Index-D.
The door itself was custom made.

We do custom made doors like that: https://rusticahardware.com/barn-door-hardware/

We sell barn door hardware. Our tracks are very high quality and have many unique features that make our tracks a great choice! Our tracks have an anti-jump piece to keep your tracks in place and a soft stopper at the end so your door isn't slamming into a piece of metal at the end of the track. Our wheels are specially designed to be completely silent and smooth! We can customize you track length and color to fit your needs and are happy to answer any questions you have! call, email or visit our website! tel:208-261-1276 info@basincustom.com, http://www.basincustom.com

Anyone know of somewhere in Australia I could have a door like this made?