Potential problem with kss.coffee
In the KssStateGenerator, a new stylesheet object gets embedded into the page via "insertRule" for every CSS rule that can have a modifier. This can be a bit dangerous because when combined with a CSS framework (like Foundation), you'll end up with a ton of embedded style tags in your page that define a pseudo class for each state.
At least in the case of IE, there's a limit to how many stylesheets a page can have. Internet Explorer allows a maximum of 31 (why that number, no clue). Any stylesheets that come after the 31st one will be ignored by IE. When I tried using this engine with a CSS framework (Foundation), that script generated over 50 separate styles that had only one selector.
Rather, it might be better to combine all selectors and styles into one style tag. I've modified kss.coffee to do this and it works for my case. It's not completely tested, however.
Take a look: https://gist.github.com/4271023