You may be interested in what we've built with React (http://facebook.github.io/react/). We're focused exclusively on rendering and wiring up event handlers and offer a super straightforward, highly performant reactive programming model. There is some particularly interesting technical aspects around how we keep state consistent between React and the browser as well as how we've architected the core (it's a bit like a game!). And it's been proven at scale (both userbase and eng org size) time and time again.
Hi Peter - React is great! To those of you who haven't already, go check it out. It shares a lot of similarities with reactive.coffee (besides our highly original names), including the "code-first" approach to building up views.
