Vision, the theme designer
I just came across Vision, a theme designer that Tobias Lütke, Justin Palmer, and friends, have built for Shopify, so you can just download the package, design your templates, and produce a Zip package ready to use with Shopify, their coming product. That is a really good way of solving the problem of making it easy for designers to design templates.
This is definitely something we could use with PublicSquare. We, too, want to let our customers create their own themes, share themes, and we want to make it easy for them to do so. It would be nice if the core of this stuff was open.