Preheat the oven to 350°F with a rack in the center position.
Bring a large pot of water to a boil. Add the head of cabbage and reduce the heat to low. Cover and cook until just tender, about 10 minutes. Transfer the cabbage to a plate cored side down and let cool.
Meanwhile, in a large skillet, heat the oil over medium-high heat. Once the oil is glistening, add the ground beef, sausage, and onions and cook, breaking up the meat with a wooden spoon, until meat is cooked through and onions are softened, about 8 minutes. Add in the garlic, salt, and pepper and cook until fragrant, about 2 minutes more. Remove the skillet from heat. Stir in the rice and tomato paste until combined.
Carefully peel the leaves away from the cooled cabbage and lay flat on a clean work surface. Add ½ cup filling to the center of each cabbage leaf. Fold the bottom half over the filling, then fold the sides over the filling and carefully roll the cabbage over. Place the cabbage rolls seam sides down in a 9x13-inch baking dish. You should have about 12 rolls.
Brush the tops of the cabbage rolls with the ketchup, then lay the bacon over top in a single layer. Cover the baking dish with foil and bake for 30 minutes. Remove the dish from the oven, discard the foil, and bake for another 15 minutes, or until bacon is crisp.
