Excellent topic, and timely, at that. I'm going to reread it again (especially Tomoo's posts) and comment later.
It's amazing what a reread will do.
Shioda, in his own way, I think, tried to get this stuff out there. Or at least explain it somewhat. As usual, the translation needed to be critically written, but without some knowledge of the subject (aiki), a translator would have a very hard time. I think if we're going to explore the possibilities that the Aikido giants did try to get this theory of aiki across, then we will have to undergo another version of translation -- this time with these core body skills in mind.
six basic movements of Yoshinkan are Hiriki no yosei 1,2 (enhancement of elbow power ,1 is for the "omote", and 2 is for the"ura" in other aikido schools), Tai no Henko 1,2 (step and change of the body,ůmaybe), Shumatsu-dosa (finishing movements).
Just what was being trained in these six? Tai no Henko is another name for sayo undo. And as we learned at Mike's workshop, there's a world of training in that one exercise. And it was interesting to read that Shumatsu-dosa was done as a relaxation method at the end of training with Ueshiba?
I don't think the problem is in finding information. I think the problem is sifting through the large piles of information out there and putting the pieces together.