QBE offer cover for pilots as opposed to just aircraft owner
http://www.qbe.com/australia/aviation/index.html
use the products link on the left
chap I spoke to was a FW crop-duster yester-year, don't recall his name though sorry.
there used to be a product specifically for contract pilots were covered on an individual basis & could use their cover to fly different aircraft &/or operators.
I think the bloke mentioned that this was targetted to Ag work, regardless product has been pulled & is no longer available.