I've taken down the preview product page for the customizable spacer I was planning to sell. Turns out, manufacturing a fully customizable product is really complicated, and I decided to go with something more manageable for my first product. I don't expect that to be a success anyway. It's all about learning.
As for the new product, I've settled on an idea and I'm currently working on the design. I'll let you know, once I have something to show.