Remove casings from sausage, and discard. Cook sausage and ground beef in a large skillet or Dutch oven over medium heat 6 minutes, stirring until meat crumbles. Add onion and garlic, and sauté 4 minutes or until beef and sausage are no longer pink. Drain and set aside. Wipe skillet clean.
Combine sauce and next 7 ingredients in skillet or Dutch oven; cook, stirring occasionally, 1 hour. Add sausage mixture and mushrooms. Cook, stirring occasionally, 1 hour and 30 minutes or until mixture thickens. Serve over linguine; sprinkle with cheese. Serve with breadsticks, if desired.