[sdiy] Tannerin/Oscillators

[med]

My friend wants a Tannerin as an instrument for his band. I've been
looking around and thinking of designs myself, and I'm wondering if
you guys can come up with a better idea than what I have.
Basically, stability in long term (over the course of a performance)
and tracking over at least 2 or 3 octaves is very much important
because the tuning needs to be done in what's hopefully a
set-and-forget fashion.
The idea for CV generation's pretty weak too. Basically, it's some
kind of gear assembly (like a steering column) that is adjusted up and
down by moving the pitch-indicator. This turns the shaft, which would
rotate a pot (or, if you guys can provide a better idea...) that would
act as a voltage divider, which would output a voltage going to a VCO.
This is not optimal because
1) output voltage is dependent on the linearity of the pot
2) it's difficult to move gears (at least in my current mental-image
of how to do it)
3) Pots deteriorate extremely quickly, especially in a stage
environment when they're being moved back and forth a lot
Now we're basically newbies here so any advice would be appreciated.
Especially on generating a voltage from a tannerin-style setup.
DCO would be a good idea if we could make it smoothly change
frequency, but I doubt we're ready for that kind of complexity.
Rock-stable though...
-MED

p.s. waveform doesn't matter, so long as it can be shaped into others.