In a large stockpot, saute the pork and beef in the oil over high heat for 10 minutes, until brown. Add the onion, garlic, and Scotch bonnet pepper; saute for 3 to 5 minutes, until the onion is translucent. Add the scallions and saute for 3 minutes. Add the taro root and saute for 3 to 5 minutes more, until translucent. Add the chicken stock, bay leaves, thyme, allspice, and ground pepper. Bring to a boil over high heat. Reduce the heat to medium and cook about 30 minutes, until the meat and taro root are tender. Stir in the callaloo. Reduce the heat and simmer about 5 minutes, until wilted. Season with salt and pepper to taste. Serve in a tureen or divide among individual soup bowls.