My apologies for taking so long to follow up on this thread! Of the two friends in NC, one no longer does armouring because of lack of space and the other is not currently taking new orders because of a backlog. I checked with my other SCA contacts and found there are several armourers in the Eastern U.S. that might be able to help you. Unfortunately, I cannot personally recommend thier work, as I have no direct experience, and I couldn't get any websites or contact inforamtion (yet).
For what it's worth, though, I had the local kingdom armour recommend GDFB (get dressed for battle) and to warn caution for "illusion Armory". Otherwise, they said to do a web search. Here is the website for GDFB (http://www.gdfb.co.uk/index.html
)and they did have an off the shelf spagenhelm....and they do do custom work. They are an European group, so shipping may not be cheap, but possibly cheaper than Australia. I'll let you know if I can find out anytyhing else. Good luck!