In Hamilton go to Nella Cutlery. They have used fillet knives up to 24". Cheap, cheap, cheap. I don't know about now but years back if you needed a sharpen you just exchanged the knife for another. Tell my cousin I sent you.
Nice to be able to catch Walleye so big a standard Rappala knife is too small. We were just talking today and I said something about the small Pic was around 5 lbs. Where we used to fish on Nippissing and the Ottawa a 5 pounder was a great Grandma that was released or mounted as a trophy. Here it's a baby. "Yo vollem." That means I love it in Croat.