Preheat oven to 350°.
In a large bowl combine bulgur and milk, stirring until combined. Let stand until milk is absorbed, about 10 minutes. Add ground beef, Italian sausage, pesto and all remaining ingredients except catsup. Using hands, mix until well combined.
Shape into 1 loaf or four small loaves, place on sheet pan. Top with catsup. Bake in preheated oven until internal temperature of meat reaches 165°; about 1 hour.
Shape meat mixture into approximately 40 meatballs (about 2 tablespoons each). Place on baking sheets lightly coated with cooking spray, bake at 450° for 15 minutes. Heat in favorite sauce for use as a main dish or appetizer. Can be frozen in zip-lock freezer bag after cooling for later use.
Fill peppers with meat mixture. Top with sprinkling of Parmesan cheese. Bake at 350° until peppers are tender and meat mixture reaches 165°; about 45 minutes to 1 hour.