In a large saucepan over medium heat, cook sausage, beef and onion until meat is browned. Drain off fat.
Stir in mushrooms, vegetable juice, tomato paste, sugar, salt, garlic powder, oregano, Worcestershire sauce, basil and pepper. Bring to boil, then reduce heat and simmer, covered, 1 hour. Garnish meaty mushroom chili with sour cream, if desired.