The 7's game is displaying good growth in the country presently, Ive said it elsewhere that the ARU and other state governing bodies will need to rationalize the 7's competition in Australia so there is a set annual program all running under the same banner, as opposed to the ad-hoc nature of things at the moment..
I think 2012 is the bet bet, the natural growth of the various competitions will be strong enough to sustain a national comp by then, assuming also that the AOC comes on board with there Olympic funding. It could be as simple as a 5 week tournament in the lead up to Christmas, this would allow S14 players to participate as part if there conditioning.
The economically sensible way to do things would be to have a overarching body established by the ARU, this body would then sanction the various events based on already established tournaments like Coffs Harbour, Gold Coast, Darwin and Noosa?. The sanctioned events would count towards the overall point tally and also receive a boost in prize money. A unified marketing formula and management would reduce costs and encourage growth.
It might start off pretty average, however it's a formula which spreads the financial burden and puts the emphasis back on the independent tournament hosts. Minimizes the risk to the ARU, it does however limit the ARU's control, which might see some reluctance.