In a new post on the Rdavid.net blog there's some discussion about Zend Framework models, the best approach and a "Service Class" idea.

After some more thought and lots of research on the subject, I’ve come to a solid point where I actually have something to try out which seems semantic aside from the naming of the class (Service Class) – but this is derived from what some people are talking about in ZF circles starting from Matthew Weier O'Phinney who was coining it as the "Gateway to the Domain" from early on, then later changing it to "Service Class".

He defines what his service class idea is - a layer between the database and each of the models that allows them to be agnostic about what kind of service they're using. He also breaks down some of the key points around his approach including the fact that the Model Service can create Forms and that the Model Service can use the Zend_Cache component directly for improving performance. Be sure to check out the comments for thought from other Zend Framework developers.