Squawk 8888,
You asked, <Correct me if I'm wrong, but don't all aircraft send fresh air into the front of the cabin and exhaust it out the back?>
In my experience (on Boeings) it is not quite as simple as that. In general conditioned air from the airconditioning packs is distributed to all aircraft zones. In addition some of that air is recirculated by means of recirc fans. The air does exit the aircraft via the outflow valve or valves which are situated at the rear of the aircraft.
So I don't think that just putting a smoking section at the rear of the aircraft would completely isolate the smokers from the non-smokers.
By the way the airlines gain a considerable amount financially by their no-smoking policy. This is achieved by lower maintenance costs in the various parts of the aircraft, particularly the outflow valves which can become considerably contaminated by cigarette tar residue. It did make you feel ill looking at that mess! No hope for me as I'm still acomplete addict despite numerous attempts to stop.
regards
Exeng
Regards
Exeng