The Apache project has released version 2.1 of Cocoon. Cocoon is described as "...a web development framework built around the concept of separation of concerns..". And in this case a concern is meant quite literally. Another way of saying this is the separation of roles such that what I'm doing as a content author does not need to concern you as a page developer, nor you as an object designer.
The achievement of this release has been described by the Apache folks as "...marking the transition from a publishing-oriented XML/XSLT server engine towards a componentized XML-based web application development framework."
Two related Apache projects are Lenya
, a Cocoon-based Content Management System and Slide
, a low-level CMS framework.
Read the official release announcement
. Find full information on Cocoon here