I don't know of any to recommend - not a sheep hunter myself. Have you considered some of the folks from the Glennallen, Gakona, Tok area? Surely there are some pilots in the Palmer / Anchorage area too. I'm surprised you have no help so far. You might try calling some of the sheep guides to see if any are also air taxi licensed and willing. What about McGrath too?
Don't know if I've added confusion - hope you find someone. I know one sheep hunter but I think he mostly walks into or boats into his hunts - one tough young man.
His pal once told how he used a rubber raft, 40 hp Jet outboard, canoe paddles, wet suit and helmets to get up to a hunt area! The helmets were for when they dumped the raft (Wrangles I think). The jet unit helped on the easy water but at times only held their place and the paddles were used to make upward progress. Sounds like a tall tale but the guy was a rock, had lots of photos of successful hunts, is a serous wolf trapper, pilot and all around hunter.
Good luck.