Just glanced, but besides a pretty UI and preview section, I'm not seeing a major difference between this and the customize section of bootstrap (http://getbootstrap.com/customize/).

Am I missing something here? What I think would be really cool is if you mashed something like this together with some prebuilt layouts (something like http://startbootstrap.com/template-categories/unstyled/), and then have more options to do slightly more complex things like a list of font selections, full-site color schemes, etc..

Anyway, not trying to put down your site. It looks pretty clean, just not seeing the need for it personally.