Mooh,
That's interesting. The reason(s) that Fred Kelly wasn't that interested in what I had to say (he was friendly, just not interested) is because he too can upstroke with the thumbpick. I asked him (to clarify) if he meant with his index finger sidled up to the thumbpick for support. He said no, he can just "free pick" it. Then he proceeded to show me over the phone. Now he did play an electric (quite ably I might add) and volume was not an issue -- so he could be very light with his touch. I'd think that would certainly help with that thumb-upstroke. He's heavily (almost exclusively) into Merle stuff.

I always figured that there were some folks out there who were going to teach themselves by sheer force of will to do that difficult upstroke.

When I hybrid I use a flatpick and middle, ring, and sometimes pinky.

Fred,
You link. I'll read. One of the first things I did when this began to occur to me is consult a lawyer to look into patent. He assured me there would be no sense in it. Fred Kelly thinks there is already some index finger flatpick out there in production, though he couldn't give a clue as to where to look.

I still think the concept is fascinating and I intend to do more experimenting.