Wiggins had cargo twin otters. Lots DZ's with them as well as wet leasing companies for DZ's. Might look into the military contractors. I know Blackwater has had a few. Possibly Dyncorp, Triple Canopy, and or others as well. Hard jobs to get but worth looking into nonetheless. There was a company in NC that was looking for Casa and DHC-6 drivers. Don't remember the name but they do a lot of "special projects".