Andrew - I think it would be doable. Check a couple of the big name manufacturers of hollow bodies and see what they are using on theirs and I think you'll find a nice range. Alternate supplier would be ALS in the Gold Coast. The Hancock Brothers that run the show have a reasonable rep. They also stock spruce specifically for archtop guitars.
http://luthierssupplies.com.au/index...Path=133_33_37
BTW - I know that the Gold Coast is no where near Mackay, but it's a whole lot closer to there than Perth. No idea what the postage costs would be to get it from the GC to Mackay - hopefully cheaper than Perth.