All of this debate is theoretical.
I took the trouble to read my way through the whole thread (which is very interesting b.t.w.!) and come to the same conclusion: A purely academical exercise.
Almost impossible to teach (at least to PPL students or low-hour private pilots) and entirely dependent on the nerve strength of both the instructor and the student. Doing 45+ degree banked turns below 500ft will scare the hell out most pilots (instructors included) even if a well researched paper predicts a favorable outcome of the maneuver. Training this procedure at a safe altitude (or in a simulator) will not help at all, because all the human factors that make it so difficult in real life will be taken away.
I would rather opt for a software solution (like an app for a smartphone or iPad) that will emit a signal once a speed/position/altitude has been reached, from which an averagely skilled and trained pilot should be able to fly a successful return maneuver within the normal operating envelope of his aeroplane (best glide speed +/- 10kt, turns with no more than 30 degrees of bank, ample reaction times). If your device hasn't beeped yet, you glide to a landing straight ahead, if you heard it beep, you are safe to turn back.