In a large saucepan, over medium-low heat, melt the 1/2 cup butter and then stir in flour, salt and pepper. Cook, stirring constantly until smooth. Add milk, stirring constantly. Heat to boiling, stirring constantly, cooking until sauce thickens, about 1 minute; remove from heat. Cook rigatoni al dente and drain well. Combine sauce with the cooked and drained rigatoni. Place half of the pasta mixture in a well-greased 9-inch baking dish. Sprinkle with evenly with the ham and half the cheeses. Top with remaining half of pasta mixture and then the cheeses. Toss the 2 tbsp. butter with the breadcrumbs and sprinkle evenly over top of casserole. Bake at 375 degrees for 30 minutes or until hot and top is lightly browned. Let set for 5 minutes before serving.