Place beef shank into a large saucepan; cover with water to 2 inches above shank. Bring to a boil; cook 1 hour or until beef is tender. Cool slightly; remove beef, discarding bone. Cut beef into large pieces; set aside.
While beef shank is cooking, combine 12 cups water and next 7 ingredients (water through bouillon cubes) in a large Dutch oven. Bring to a boil; reduce heat, and simmer 30 minutes or until vegetables are crisp-tender. Ladle soup into large bowls, and top with beef. Serve with lime and cilantro.