Forgive the waste of time if you already did this but....when you talked to Foss did you give them dimensions on the rudder? Shaft diameter length and thickness of blade etc? Although your rudder may be out of production perhaps they may have a production rudder available that is close that may only need slight modifications to make work. I know of a guy that had a rudder fail on his 34 foot production boat and the maker wanted 4K for a replacement. What he did was but a Hunter 37.5 rudder from Foss and as the rudder post was the right diameter and orientation, he modified the blade profile to match his old one.