What you show is a Rapala fillet knife. The Martini blades are marketed by Rapala. Great knife, you're right. Unfortunately, the 2002 catalog doesn't show the spoon on any of the versions, so any you find are back stock.

You're limited to cutting most of the handle off a Goodwill spoon and epoxying the stub into the handle of the knife. I've got one with a wooden handle that might find itself altered soon

If enough people squeak, you might get Normark (the US distributor) to bring it back.

Keith