[RWP] tiny synth box for vocoder?

[Indigo]

I'd like to find a used synth module, as small a footprint as possible, 
to drive a vocoder with.
Yes, I could use a voice from another 61 key midi keyboard, but how 
handy it would be to chain a small synth module set to a sawtooth wave 
into my new TC Helicon vocoder box; and drive it from midi sent out my 
Casio XW-G1 keyboard.
So, size on this cluttered desk matters; and it matters that it be 
quiet, but I don't need to love its presets, since you don't hear them 
through the vocoder.
The preset called Dance Lead or Super Sawtooth are typical presets good 
for driving a vocoder, also good for driving a plastic-tube-in-the-mouth 
classic TalkBox.
I'd need to be able to send ordinary midi messages to the little synth 
box, like all the range of midi notes, also mod wheel and pitchBend.
So, if you can recommend a tiny dependable synth module from the past; 
I'll look for one on ebay to drive the vocoder.

Thanks,
Indi