Why not tack it on to Bitcoin Alive in Sydney?

You'd have to have it on the preceding Friday or the following Monday but you would have a number of Bitcoiners already in the area.

All you'd need is a venue.

Another option would be a Nostralian Bitcoin Bush Bash in Beechworth early next year (either before or after BA). The date for this Bitcoin bush bash is up in the air because BA took the usual scheduled date for it.