I've looked around and no luck but have discussed it with my uncle who owns a machine/ fabrication shop. I'm sure if there was real interest in the idea, he might be willing to do some prototypes. We've talked about the possibility of either rounded outer (a la phil wood/ paul) with a unique tool or a unique hexagonal outer. Either one would require a special tool, which I guess would be the point of it to give it anti-theft properties.