Check with your local butcher. Also: Check the docks and see where the mates are getting their filet/boning knives. Often there is a service involved. A company who services these accounts. Forschner, Chicago Cutlery and others are used by these guys. Sometimes they sell "re-grinds" also. You may be surprised at what you can find. In an exotic location...such as a really "long" island...I'm sure such a service is available.
Good luck, Capt. Chris
PS: Tony: What's with the Yankee's start this year?