Another thought. Have you had a look at the recipe for the SummerNats held in canberra. I went to one a few years back and it was awesome. As with what alot of the other guys are saying, lots of tarts - they came from every where, wet t-shirt comps (might be a bit tought in winter), burnout comps, dyno shoot outs, etc. Then add some drifting demos - how many people would love to have a thrash around a circuit for under the cost of Barbegello race way? I'd say you'd get a few takers. They also did a street parade, spose that helps drum up more interest with the public, which means better attendance, better media coverage, better profile for import owners and more money into displays.
EDIT: maybe even combine the show with a national drift event, get some interstate interest - now that would be nice to see.