Place beans in large bowl. Add enough cold water to cover. Let stand overnight. Drain beans. Toast cumin seeds in heavy small skillet over medium heat until fragrant, about 4 minutes. Transfer to spice grinder and grind finely. Heat oil in heavy large pot over medium heat. Add bacon and fry until cooked but not crisp. Add celery, both bell peppers, chilies, onion and garlic and stir 1 minute. Mix in 3 tablespoons of ground toasted cumin, ham hock and bay leaves. Add beans and cook 3 minutes. Add Madeira and thyme and cook 1 minute. Pour in enough stock to cover beans by 1 to 2 inches. Simmer until tender, about 2 hours (time will vary depending on dryness of beans). Remove ham hock from beans. Cut off skin; remove meat from bone. Dice or shred and return to pot. Add cracked pepper. Season with salt and serve. (Can be prepared 3 days ahead. Refrigerate. Reheat just before serving.) Makes 8 cups. side 03