Mix ground beef, rice, egg, onion, carrot, salt and pepper. Mix together vinegar, brown sugar and tomato sauce. Drop cabbage in boiling water for 5 to 10 minutes. Remove 10 large leaves. Chop remaining cabbage. Place in bottom of crockpot. Place 2 to 4 tb of meat mixture in center of each leaf. Roll up and use toothpick to hold. Place stem side down in crockpot. Pour on tomato mixture. Cover and cook on LOW for 8 to 10 hours.