Colossal

Twism: 120ft long, 22ft tall, 15 ft wide, 135 ft max wingspan, 60 ft min wingspan. Average (minimum) weight: 1,280,000 lbs (or about 640 tons-if my math is right). Dimensions for a great wyrm Gold dragon.

Source: Draconomicon (The Book of Dragoms) p. 46-48