Not trying to piss you off becasue I know this is your bread and butter here, but I have to ask. If this design was that important for you to keep for yourself, then why did you let Carlos put it up on his site? I mean, it’s just sitting there taunting young 3D artists (digital and traditional) to make their own versions of it. Pretty much everything Carlos does is inspirational, so it seems a litle unreasonable to ask someone to not be inspired by something they’ve seen. Just a thought.
I do understand how you feel though. If I paid money for a design, I wouldn’t want anyone else using it either.
Looks like Carlos was a little inspired himself from an old Vincent Guastini design: http://www.vincentguastiniproductions.com/METASPAWN1.jpg