Joubert described the Jet Turn many years ago but it was an up-unweighted turn for sure.
Bruce--if you have not already, I encourage you to review the recent thread about "Cross-over vs. Cross-under,"
which is (for better or worse) largely a discussion about extension (up-unweighted, if you will) vs. retraction (down-unweighted) transitions. You seem convinced that there is a dramatic difference between the two, but I believe that the discussion in that thread very much blurs the distinction, and suggests that it is more of a continuum, at least. In modern turns, I submit that "extension and retraction turns" represent more the ends of a spectrum, and that they are not so much different and opposed techniques as they are simply extreme examples of what is really just the constant management of pressure and "loft" of the center of mass through the transition and throughout the turn--situationally dependent.
The "move" I believe you have identified is not automatic or magic, but when done correctly, it may well feel like it is. The new turn will start without any apparent effort on your part, as the movements that cause it to begin are merely continuations of the movements already occurring when you exited the "control" or "shaping" phase of the previous turn. You need to make no effort--literally--as those movements continue entirely by virtue of their own momentum.
Because none of the movements of the turn initiation actually begin at the beginning of the turn, teaching this concept is no simple task. What must you do to learn, when the goal is to do nothing? That is one of the reasons why your progression--well intended as it may be--does not work for me. In particular, as I noted some time ago in this thread, the critical part of this is that the ideal movements began in the previous turn, while much of your progression begins from traverses. As SkiDude has suggested, an active "counter-steering" movement can motivate the "toppling" ("falling" into the turn) that all good turns require, when beginning from a traverse or straight run--just as on a bicycle (which may be a better analogy for skiing than a massively heavy motorcycle). But your wedges (stems) involve lateral ski movements--very much in contrast with the gliding/carving movements of skis in high-performance turns. Indeed, the very thing that makes the transition feel "automatic" is absent when the turn begins from a traverse.
Furthermore, as we have much discussed in other threads on the topic, the "forward movement" of the feet that you have accurately (in my opinion) identified in high-performance turn transitions represents more the facts that a) the feet and skis move faster than the body on their longer paths, and b) the movement of your feet is not so much "forward" as in a direction that will be, later
in the turn when you re-establish pressure, out to the side
--in other words, laterally, to the outside of the turn. For both of these reasons, it is a movement that must be MUCH more subtle at low speeds, where the skis' path will never be nearly as far to the outside of the body's path, and the speed differences between feet and body are negligible. That's why the forward foot movements you show in your low-speed turns put you way in the back seat and on the inside ski. The resemblance between those forward and lateral movements in your wedge turns and the accurate movements of a racer at high speed is superficial at best. In your low-speed demos, the movement is mis-timed (starts at the initiation), wrongly motivated (you push your feet, rather than allowing their momentum to carry them accurately), and overly intense ("too dynamic") for those slow turns.
You might argue that they still do resemble the movements high-speed World Cup racers use and that your progression seeks to introduce the "right" movements, even in the wrong situation, so that when the student picks up enough speed they will work perfectly. There is possibly some merit to that approach, but it is not one that I generally condone.
Anyway, again, I give you credit for bucking the dogma and popular opinion, and putting your ideas out there for scrutiny. That's never easy. There are many high-level instructors and coaches who, while perhaps considerably more experienced and skilled than you, lack the courage to question dogma.