Folks, the quest has ended! I popped "Neanderthal spelling change" in Google and got a load of hits with excerpts and discussions addressing the question directly, as well as some interesting looks at German orthography ala the TH/T change. So there it is for anyone who is interested. I'm through the first 6 hits, and when I surmise the most concise and informative I'll post it here to wrap this up.