Jasondiver -- As Grateful Diver wrote, I was involved with encouraging PADI to revisit the notion of "On the knees" although I have zero idea how much my involvement meant to them. The group that co-edited "the article" in PADI's Underwater Journal which did lead to the revision included me and my wife, Lynne Flaherty, as well as other instructors from around the world. What was interesting is that we all (that is the instructors involved with writing/editing the article) had slightly different techniques for this but we all had one thing in common -- no knees, ever (well, my students can be on their knees if they can also stick their head out of the water at the same time!).
After August I didn't know if I would teach again but I am now, slowly, getting back into it (I have one private student who, on his first day of pool work, was doing his skills mid-water and motionless by the end of the session just because he could). I am organizing an Open Water Class through a local Church as part of the Church's environmental community outreach.
For what it's worth, it is my experience that it takes LESS time to teach students this way, they have more fun and "control" is much easier. (Query -- which way does a student bolt when she is on her knees as opposed to being flat in front of you?) The key to being able to teach this way, again in my experience, is being able to always have all staff neutral and able to perform all skills while in the water column and motionless. For what it's worth, I don't know how you can do this without a back kick either.
And thanks to all who mentioned me -- I'm honored by your comments -- particularly knowing how good all of YOU are.