noel,
like a few others have said the imports tend to head down in their own little organized events, i.e. skidpans, track days, etc.
that said - there is a serious lack of QLD facilities and support in motorsport, one look at all the regulations and rules involved with places like mt. cotton, lakeside, darlington park, etc. there's no wonder why events like the upcoming skidpan is planned 2 months in advance at a facility 2 hours away.
here's another: go start an event build it and they will come, you'd be surprised at the turn out for a well planned outing
cheers
eug