Just done a bit of research.. I suggest heading to the track.
Bookmakers at Doomben and Eagle Farm are required 'BY LAW' to accept bets up to the following maximum amounts:

Doomben/Eagle Farm - Saturday/Midweek - Local and Southern Events.
Rails Ring - $2000 WIN
Main Ring - $1000 WIN

Local Rule 131, Queensland Racing Committee.

So even if you are cleaning them up continuously every Saturday, say even 2 units. That is still $4,000 per week, and the pricks must take your bet!

Anyone have any info on Southern State betting rings, I cannot find anything on these websites.

Cheers,