Ross B said:
Local might be the way to go in the States, but the Australian screenprinters I have sought quotes from are BLOODY expensive in comparison. So much so, that I am investigating getting prints done in the US!
Have you checked the east coast of Australia? I know of at least one seller in Perth (unless this was you...?

) who sources their printing from Melbourne, raising the possibility that it's a Perth thing and not an Australian thing.
It doesn't hurt to investigate, but given how strong the printing industry is here I doubt it would be necessary.
Ross B said:
And the cost of quality blanks is also MUCH cheaper in the States.
This is true, but will be affected by what you're after. If you want the cheapest blanks possible, it's potentially cheaper to import. If you want sweatshop free, it costs about the same to buy them locally as to import, and the environmental impact is lessened (i.e. no shipping a product from the other side of the world that can be sourced locally). Even cheap blanks aren't that cheap (relatively speaking) by the time you pay shipping and tax.
(for the record I do, in fact, import most of my blanks from the US - so I'm mentioning this as information, not criticism)
Ross B said:
I believe Aust Customs don't charge duty on internet orders valued at less than $1000
For starters it makes no difference whether it's an internet order, a wholesale purchase order made through a company, an item sent from a friend they didn't mark "gift", etc.
Customs duty
can be charged on
all imported goods, whatever the value. There's a discretionary limit - below that they don't
have to charge import taxes (and they won't), but they always retain the right to. Over the limit they are supposed to charge import duties.
The discretionary limit is different for Australia Post and for couriers - for couriers it is $250, for Australia Post it is $500. In theory if you are over those limits you will be charged import duty. The reality is that this is somewhat randomly enforced - I've known plenty of people to get expensive things sent over (e.g. a two thousand dollar camera lense) and not have to pay duty, and others to get caught out on things just over the limit. I think technically you are supposed to report items yourself and volunteer the tax, but obviously that happens about one time in a million.
I think freight companies are a lot more stringent about enforcing the rules, as they have a lot more to lose. Australia Post are quite lax, and while I don't know for sure I would speculate that's not the case with FedEx, UPS, et al.