[sdiy] CV-vactrol circuit

[niroke at tampabay.rr.com]

Can anyone direct me to a CV-Vactrol circuit which I can build and make for others which is not bound by any legal restriction?  

 I foolishly resigned a currently-available product to suit my needs and for my own use.  I wound up having extra boards made because of a mistake on the first batch (well, there's a mistake on the second batch too), so I have more than I can use.  I wanted to be able to give them away to people building the same project.  I have now asked the manufacturer of the circuit I copied for permission to use the boards, cite him as the origin, and give the extra boards away, and have offered to collect some remuneration as a royalty.  I have not yet had a response, but I figure I should prepare for the worst, and will completely understand if that designer will feel cheated out of income for his IP.  

I already have the schematics, two factory modules, and permission to build clones of Doepfer's discontinued A-101-9 universal vactrol module, but that circuit is a bit more involved than necessary.  Also, I was only given the schematics and permission on the condition that I never share them or build for others.  I'd prefer to use a circuit that I can make available to other builders.  

Anyone one recall a suitable circuit that's free to use?

Thanks,
Nick