The video from my CSSConf talk on CSS Performance Tooling is now up. This goes along with the slides I've previously posted. Hope it's useful!
Abstract: High-performance sites need to feel instant and deliver the goods in < 1000ms. In this talk, learn about the bleeding edge tools that can automate keeping your CSS on the fast path. Automate generating critical-path CSS, removing unused CSS, discovering duplicate selectors, colors and more.
PS: Since posting this video, Stefan Judis and Marco Biedermann have put together a new performance tooling site you may find helpful.