On our sister site, AjaxDeveloper.org today, there's a new post with a pointer to this Ajax Magazine post discussing Claw.

Claw is a PHP5 framework which provides a convenient and intuitive way of developing PHP5-driven object oriented Web applications. It allows developing tree-structured Web applications with ease. Claw is a very new project at its alpha stage, but already offer lot of great features.

Most of PHP frameworks lack a solution for tree-structure web sites. In many real world applications the usual "module/action/variables" approach is simply not enough. Claw allows developing tree-structured web applications with ease.

They also link to the documentation for the project, as well as a simple demo to get the ball rolling...