One step closer...
Went to a nearby used game/music shop today that has a basement 'Museum' where they store stuff they feel is too obscure to put on the shelves. A few months back, I landed the Atari 2600 and Steering Wheel modules for the Colecovision for $20. Today, I got the Odyssey 2 Voice Module CiB for $60!
The cheap prices are due to their untested states... But I got this home, tried it out myself and the gamble paid off!