Just bought a piece from eBay, came from over east. Was $22. Might be worth asking around here, I think jimbo makes his own strops, someone might have a strip kicking around for some kind of trade.
There is a bloke who had a good leather supply place, just going into Freo, he is operating from home, I will have to look for his card, but he has roo hide, and bark tanned leather from NZ as well.