You mean CANADIAN Walleye. Michael Hoffman pretty much said it all. Even in Minnesota where the Walleye is much more available it is still mostly Canadian except in a few instances like annpeeples experienced.
My collection and mostly Minnesotan. http://web.mac.com/davydd/Site/Comfort_Cuisine/Pages/Walleye_Sandwiches.html
Just by reputation the Tavern on Grand in St. Paul, MN is the signature source in the Twin Cities though there are many just as good and maybe better. The Walleye sandwich is almost a necessary addition to every bar/grill and restaurant in Minnesota that serves fish sandwiches where perch and whitefish might take precedent in Wisconsin and Michigan.