Preheat barbecue grill to medium. Cut bacon into suitable pieces, depending on the size of scallops and wrap them around the scallops. Alternate onion, bacon wrapped scallops, pineapple and tomato on long skewers. Mix butter, Worcestershire sauce, and lemon juice together; season with pepper. Brush mixture over skewers and place them on the barbecue grill. Cook 5 to 6 minutes. Be sure to rotate skewers and baste/season during cooking. Makes 4 servings. You can also broil these skewers in the oven. Be sure to rotate and baste regularly, as mentioned above.