Combine crab, shrimp, mayonnaise, green onion, salt, pepper, lemon juice and Tabasco in a bowl. Divide and spread this mixture on one side, of three of the toasted bread slices. Top each with 2 slices of the bacon, and then top with another toasted bread slice. Top those bread slices with an equal amount of the tomatoes and shredded lettuce, and then set on the remaining bread slices. Secure the sandwiches with toothpicks, if desired, and cut each one into four quarters. Serve three sandwich quarters per serving.