Place ham bone into a large pot and fill it with enough water to cover. Bring to a boil and cook for 15 minutes. Add onion and tomatoes, then stir in frozen mixed vegetables and potatoes. Simmer for about 20 minutes, then add macaroni, rice, and chopped ham. Cover and simmer over medium-low heat for 1 1/2 hours. Any ham on the bone should come off easily. Stir in tomato sauce and let cool for about 15 minutes before serving.