Ask YC: Anyone ever heard of Coset? (Ruby Webservice Framework)

I was reading this presentation^ about Rack, and it had a couple slides on something called Coset, which looked like a great way to build RESTful services on top of Rack. The problem is, I can't find Coset anywhere in my Google searches (other than the presentation). Anyone have some pointers/experience with it?

^ http://chneukirchen.org/talks/euruko-2007/chneukirchen-euruko2007-introducing-rack.pdf (Slides 30-32)