Hello lpojibwa,There is a great deal of history in all of my moulds and a story behind the design of almost every one. I have even included a section in my memoirs devoted to weight moulds.
Where can we read those memoirs? Sounds like it might be an interesting read.
What about some neck weight moulds? Have a look at the one in this thread http://forums.deeperblue.com/freediving-equipment/81834-different-neckweight.html (and I do not mean the one from myself, but perhaps something in the way of the one from Sgnips). Just it would be good if it allowed for some weight fine-tuning - some form of attaching smaller subweights. However, I am afraid it is commercially uninteresting, and frankly told, even if you had a perfect one, I am not sure if you'd manage to sell any at all, so don't waste your time on it unless you find some takers for it.
BTW, if you want some boost in promoting your moulds, feel free to submit an avertising banner on my website. I display 200,000-400,000 banners monthly free of any charge.