Wow, I have not seen this either. Its like a cross between a standard Vetter Sound and the one that came in the Liberator fairing.
Do you have any more information on this? Can you take some more images? Does it fit in a Windjammer?
It is post Cycle Sound, so it was after Craig sold the company, however it does have the Vetter icon still, so I believe it was before he was actually gone.
Interesting.