I was under the impression that the E3 had an attached dependent visa already: http://canberra.usembassy.gov/e3visa/dependents.html
ie, Go to the US to work for your business, and take your partner along who'd be able to work wherever they'd please.
The point I was trying to make is that the E3 is possibly a better option than a H1B for any Australians interested in working in the US.