MOTM

http://www.analoguesystems.co.uk/controllers.htm

Scroll down; they've got a version of the Sorcerer called the Demon that is a 
stand-alone CV keyboard with built-in joystick.  Not cheap, but looks decent 
(although it has those annoying 1/8" jacks).

Look at the bottom of the page too... I think the French Connection is based 
on the Ondes Martenot.

Question is... do you spend twice as much and just wait for the Big Briar 
Voyager?

Ivan