Cook and stir sausage in large skillet on medium heat 5 minutes or until browned. Add onion and bell pepper; cook and stir 5 minutes. Set aside.
Arrange 1/2 of the bread slices in single layer in 13x9-inch baking dish. Top with 1/2 of the sausage mixture. Sprinkle with Parmesan cheese and 1/2 cup of the mozzarella cheese. Layer with 1/2 of the tomato slices and remaining bread slices. Top with remaining sausage mixture and tomato slices.
Beat eggs in large bowl with wire whisk. Add milk, Italian seasoning, garlic powder, red pepper and salt; mix well. Gradually pour into baking dish. Sprinkle with remaining 1 1/2 cups mozzarella cheese. Sprinkle lightly with additional Italian seasoning, if desired. Cover with plastic wrap. Refrigerate least 1 hour or overnight. (If refrigerated overnight, let strata stand at room temperature 1 hour before baking.)
Preheat oven to 325°F. Bake 55 to 60 minutes or until center of strata is set and top is lightly browned. Let stand 10 minutes before serving.