This issue was discussed recently, with some definitive statements by Boeing, on the
B737 QRH Questions thread.
Shore Guy, Hoot Gibson was
accused of operating a 727-100 with the trailing edge flap out, and the leading edge devices disabled by pulling a circuit breaker. Something he has always denied, by the way. There is significant evidence that this accusation was
completely groundless, and that the actuator for the leading edge device may have failed in flight.