Preheat the oven to 375°F. Slice the tops off the bell peppers and remove the seeds and inner membranes. Arrange the peppers upright in a deep baking dish.
In a bowl, combine the ground beef, crumbled bacon, 1/2 cup cheddar, egg, breadcrumbs, diced onion, 2 tablespoons ketchup, mustard, smoked paprika, garlic powder, salt, and black pepper. Mix gently until just combined.
In a separate bowl, stir together the rinsed rice, diced tomatoes with their juice, and beef broth. Pour the mixture around the peppers in the baking dish.
Divide the meat mixture among the peppers, packing it in gently without pressing too firmly. Spoon 1/2 teaspoon ketchup over each filled pepper.
Cover the dish tightly with foil and bake for 55 minutes. Carefully remove the foil and check that the rice is tender and the beef is fully cooked. If the rice still feels firm, cover the dish again and bake for another 10 to 15 minutes.
Sprinkle the remaining 1/2 cup cheddar over the peppers. Bake uncovered for 5 to 8 minutes, until the cheese is melted. Let the peppers rest for 5 minutes before serving with the tomato rice from the dish.