Robert M Watson Jr
Perhaps I've misunderstood .. I thought Dan Harden was focusing on instructing instructors so they can go out and instruct (was that not one of the reasons behind the recent seminar?).
No, that definitely seems to be his intent, and it's an exciting trend. What I meant was that you've got three guys who are widely held to be lightyears ahead of most. There could be others, but these are three who a fair number of high rankers (in a variety of arts, but for the sake of this site, maybe it's enough just to focus on aikido sensei) say have the goods. So why not just cut to the chase and go to them first (if you have the opportunity), as opposed to having to weed through potentially questionable recommendations. And as much of a tired cliche as it can sound like, it really does have to be felt. Once you have, your radar for this stuff becomes a lot sharper.
You're absolutely right that, in time, this stuff will disseminate (that is, if people are working on it correctly, and consistently), but it won't happen right away. You may get some time with X-Sensei, Aikikai 6dan, who's been learning from one of these gents, and feel amazing things, but I'm willing to bet you it's only nascent ability. Better than people who don't know how to do this? Sure. Anywhere close to having a firm and consistent grasp on this? Maybe in a year or two. Or more - who knows?
That's why I recommend you (really, anyone who's interested in this) to politely contact one of the three who teach this regularly, and join the festivities. If you're able to do so, and practice this stuff consistently and actively, there's no reason to say you'll be much farther behind those 5th and 6th dan. The reason those high rankers are talked about so much isn't because they have any more inherent capacity for this stuff than you do, but because they're the ones who will be able to effect broader systemic change much more directly (or cause wider schismatic unpleasantness - again, who knows? Not a bad thing in either case).