OK, I have a somewhat different proposal:
System-Wars (a most popular forum at the ANHC's).
Choose (f'rinstance) 5 or 6 brewers (volunteers..) around Melb., who reckon they can knock-out multiple brews in a single day.
Stipulate the styles to be brewed & each BM gets to choose the styles they brew & the order they do it in.
Folks from different areas attend the brew-day closest to them & act as adjudicators to make sure the "rules" are adhered-to, take photo's as proof etc...
Each "group" act as a team & ferment the resulting beers for future swapping & evaluation.
The MB plans & produces as many different beers as they can in a single day (start/finish timeframes to be stipulated in the rules) with their system.
Minimum 20L batch-size. At least one batch has to be in the fermenter by end-of-play (ie. no restrictions on cubing).
I haven't thought this through in detail, but it might make for a fun day for folks that can't travel too far for one single mega-session.