Adam Jensen has added another post (a followup to a previous one looking at Zend Framework modules) about a "first draft" of a practical application of the topic - the code for a Zend Framework content model.
With this post, I'd like to introduce my new Zend Framework "content" module, which provides several abstract components for a reusable model layer, along with a concrete framework for building a variety of content types sharing a common database-based persistence layer. With some (OK, a lot of) refinements, a module like this could easily form the foundation of an extremely extensible Zend Framework-based content management system.
The code (on a public svn repo) gives you an abstract model/mapper system, a content model and a view layer bundled with a few helpers and and filters tossed in. Check out his post for more information on licensing, use and the current state of the project.