Don't know much about immigration, however there are Aussies, Brits, Indian, Malayss, etc flying heavy helos for Canadian Companies. I guess what I am saying is that it is possible to get over here. Try Canadian Helicopters, Couger Helicopters, Helijet Airways, they should all have websites. The only civil CH-47's that I know of are heli-logging with Helifor. Coulson Aircrane and Eriksson (USA) are a couple of other loggers with heavy gear. Try the Website for Helicopters magazine, they publish an operators directory every year and you can subscribe online.
http://www.helicoptersmagazine.com/
Good Luck.
PS What's the SK-61/76 market in Aus like?