Melt 1/4 cup butter in a large skillet over medium-high heat. Add shrimp, crabmeat, and green onions, and sauté for 1 minute. Stir in vermouth, salt, and pepper. Bring mixture to a boil, and cook 7 minutes or until most of liquid is absorbed. Remove mixture from heat, and set aside.
Drizzle 1/2 tablespoon melted butter into a 13- x 9-inch baking dish.
Stir 2 cups Wine-Cheese Sauce into shrimp mixture. Spoon about 3 tablespoons shrimp mixture down center of each Crêpe.
Roll up, and place, seam side down, in prepared dish. Spoon remaining 2 cups Wine-Cheese Sauce over Crêpes. Sprinkle with Swiss cheese, and dot with remaining 1/4 cup butter. Cover and chill for 3 hours. Let stand at room temperature 30 minutes.
Bake at 450° for 20 minutes or until thoroughly heated. Garnish, if desired.