Australia will not have a Silicon Valley until the banks let Australian startups charge their customers in USD.
That essentially it's Paypal, Worldpay or NAB.
There's a startup opportunity here - it doesn't need to be Google Checkout or Stripe - and, because it would benefit Australian business, it would make sense for the government to fund it (ha).
Yet another good reason to outsource payment processing, and concentrate instead on what you do well.
I use FastSpring because they are good at the headaches of making it easy for people to pay whenever, however, in whatever currency they like.
"Having a Silicon Valley" is totally unrelated I think.
There may be some sectors which you could say you can't compete in on a global stage from Australia because of payment processing fees but it really wouldn't be many. What is the big deal about setting up a US company to handle it? Why not charge US customers in USD?
There are so many options that to dismiss running a business from Australia because of the extra few % really may be a problem in your business plan and product instead of payment processing options/cost.
Are you doing recurring billing with PayPal? If so, I'd love to know how!
Aside from this Australia is a good place to run a startup, there's a good community in most of the major cities.