In the search for an answer for this camber question, I have found the document of the patented THS system invented by Airbus Industrie (
Process for improving the maneuverability of an aircraft during a resource - AIRBUS France please open the PDF).
I know its not much but, the drawings of the THS show a profile with a "neutral wing" (sorry, can't remember the correct name of that wing type).
Please note the last claim of the "paper":
2. The process of claim 1, wherein said initial flight phase is a cruising flight and said resultant aerodynamic force is at least approximately zero.
I'm not sure if I'm right but, it seems understandable to me, that in view of the new flight controls systems and new aerodynamic designs, that a solution other than a down camber stabilizer wing would suite the needs for fuel efficiency.
P.S.- By the way, the pictures posted by Confiture were taken from below and do not give a correct idea of the profile of the wing/stab. So, I am still not convinced...