Omnisio (YC startup) is founded by Aussies and based here in the valley.
"... Which begs the question “do ‘aussie’ startups really need them?” Could the continual scarcity of capital and local entrepreneurial mentoring, be a breeding ground for a new form of Startup? ... and you said:`I think this is exactly the type of startup YC breeds` ..." ~
I added this comment before I posted here and while I didn't have Omnisio specifically in mind you pretty much confirm what I suspected.
It's funny - 100,000 ex-pat Aussies in California, and I only ever run into people I went to uni with and are now working for Google.
There are a few efforts underway to try and build a stronger aussie community in the bay area. Check out www.advance.org and sign up. I'm on the San Francisco committee and specifically thinking about ways to get entrepreneurial-minded Aussies together.