Sorry it's taken me so long to get back to this, but I have meant to reply
to it all along . . . .

David, I looked over your vowel alternations and loved them.  However,
when I sat down to do an internal reconstruction, I couldn't come up with
anything that made sense and wasn't unbearably complicated.  What's the
historical basis for the alternations?  All of my complicated scribbling
was eventually for naught, and now I'm dying to know where all of this
came from, and why.

If you'd like, I'll post some of my notes and guesses about the historical
origins of the vowel harmony system, too.

Jesse S. Bangs [log in to unmask]

"If you look at a thing nine hundred and ninety-nine times, you are
perfectly safe; if you look at it the thousandth time, you are in
frightful danger of seeing it for the first time."
--G.K. Chesterton