This sounds like a great idea. I wasn't clear from the post: is this going to be a web app?

Is it similar to: http://divshot.com https://www.easel.io/bootstrap http://jetstrap.com

Yes, it's a web app, but not subscription based. Essentially: create account, create toolkit, pay, download.

No drag and drop, WYSIWYG stuff like the others you linked. Purely focused on customizing a design style.

Hope that answers your question.

The fonts look awful on Chrome for Windows (Version 23.0.1271.97 m)

Sorry about that. The hinting on Calluna via Typekit isn't so great. I need to switch to a different font for paragraphs.

I Was blaming Chrome, not you :-) I hope your project is a success.