I have an answer from Eventide, the H3000 will do the MIDI-controlled
8-voice pitch shifting what I described. They are also working on a
native version of the Eventide Octavox plugin that will eventually do
the same thing in software, but it is not out yet.
The Pro Tools Octavox costs ~ $500 anyway, I almost scored a used
H3000 on ebay for that in March.