If your aircraft has very good glide performance a turnback may be possible. As has been said gliders, PC-12 and some light aircraft with either good rate of climb after take-off or very high aspect wings will have a chance.
The problem has been those that have thought it possible in a Lance, Bonanza or similar that have stalled and crashed as a result. Some have been over open cattle country at the time which was little worse than a poorly maintained grass strip. The ATSB has many unfortunate acounts of attempted turnbacks which have resulted in loss of life. There are also many occurances of off airport landings which have been sucessful (light injuries with no loss of life).
Two major issues with a turnback are;
1. The much greater risk of loss of control.
2. Increased groundspeed at impact if any headwind was used on take-off.
In the case of the 30 kt headwind your ground speed at impact would be 60 kts greater turning back, that's assuming you were under control and used full flap and minimum touchdown speed. In a trainer your groundspeed at touchdown landing ahead in these circumstances would be less than 20 knots, even if you hit things it would be survivable.
The blanket “don’t turn back” is a good one to teach in my view, because it is very dangerous, and if you haven’t trained for it you’ll be putting yourself in a very poor situation. However, in the situation Chimbu described a logical series of steps were followed beginning with high altitude trials and progressing to a realistic situation.
This seems to me to give them the knowledge of under what weather conditions, at what height, and in what manner a turn back can be accomplished in their aircraft.
Agreed
Its also good to remember that even in your aircraft a lot of things can change, especially if damage causing additional drag or airfoil deformation occured with the failure. Attempting a high wing loading maneuvre at low speed with damage to the airframe could result in anything.