The broad concept seems to be non-competitive, closed roads, typically speed limited to around 140kph and with an average speed limit/target time.
This kind of things looks like exactly what I'd like to do, given all that I really want is a chance to drive some nice roads at a quick pace with the road to myself, I'm not bothered about competition really, and I'm in no way game to attack those sort of roads at race pace!

The ones I have spotted so far are:
Various Victorian ones run by http://www.mountainmotorsports.com.au/ - All look good, but they're shocking at updating the website - some places suggest the Baw Baw sprint is cancelled, and yet there is no mention of it on that website, so I wonder if they even still exist!
The Targa Tassie Tour - Looks great but realistically a $7k+ proposition
Adelaide Hills Thoroughbred Challenge - Looks awesome, paticularly with the "not too slow, not too fast" scoring system so there actually is some competition.
Can any one recommend anything else of this nature, or has anyone here done one of these events?