There are a number of sites/webapps that do this already. I think the fact that it is a standalone app is actually kind of refreshing and opens them up for thin

There are a number of sites/webapps that do this already. I think the fact that it is a standalone app is actually kind of refreshing and opens them up for things like inclusion in the Mac App store. http://easel.io http://easel.io http://divshot.com http://divshot.com http://jetstrap.com http://jetstrap.com All do this directly at: http://www.bootstraphero.com/the-big-badass-list-of-twitter-bootstrap-resources#interfacebuilder http://www.bootstraphero.com/the-big-badass-list-of-twitter-... There are a bunch of web apps that do aspects of this (button, form and theme builders).