Please remember that the Summer Field Day is 3rd weekend in January each year.
Maybe pick the first full weekend regardless of date (eg even New Years Day).
Maybe something unique at VHF/UHF in VK is in order if you want to do an event over a weekend.
Call it a 1-day event, either just one calendar day (Sat OR Sun) from 5AM to 10PM, or 0100UTC Sat to 0059UTC Sunday (like the VHF FDs), with a shorter period option eg 6 hours.
Given the recent-ish move to, and interest in, FT8, make it similar to a FD in basic concept but digital only and no portable requirements,
6M, 2M and 70CM only, single or multiband.
Use any of the digital modes, with extra points for MS contacts, (maybe moonbounce only within VK/ZL) etc... due to extra complexity.
Typical Sporadic E in early January will make for lots of possible contacts Australia wide.. with NZ and other nearby countries too.
It could still be a (re-engineered) Ross Hull Contest by name, and given his experimentation and forward-thinking, it travels the same path into new ways.
Many operators now have interfaces between PC and radio and this would just need a move of the radio to 6M, 2M or 70CM.
WSJT-X has contesting features and outputs Cabrillo files that could be the log entries, set the rules to match what is already in that software. See page 2 in
https://physics.princeton.edu/pulsar/k1jt/Quick_Start_WSJT-X_2.0.pdf "Generation of default messages for Fox, Hound, NA VHF Contest, EU VHF Contest, ARRL Field Day, and ARRL RTTY Roundup can be activated through selections on the Settings | Advanced tab"
Email in the Cabrillo and all is done. Minimal cover sheet required - it's mostly in the log file. The contest manager's processing code works out the scores.
Best scores in each digital mode category or mixed mode category are defined as the winners.
You might find far more entries arrive than the 8-10-12 for the existing event.
Over 6 months to implement the change.
You asked, I answered.