The Brisbane to Sydney commute is neither international nor that much longer than the Glasgow to London commute which many already do (not daily of course). My husband quite frequently flies to London, stays a night or two to work in his London office, then flies back all at the expense of his company.
As Roberta2 pointed out, some companies would cover the cost if your skills are in demand.
However, as we're exploring all options and not just pouring over 'pretty pictures of Brisbane on the Internet' we've taken into consideration, points made by some about the Brisbane/Sydney commute and that long term it wouldn't be a feasible option.
Thanks