Here are some Rapid Development Frameworks for PHP:

Prado PHP Framework:
PRADO is a component-based and event-driven framework for rapid Web programming in PHP 5. PRADO reconceptualizes Web application development in terms of components, events and properties instead of procedures, URLs and query parameters.

Cake PHP:
Cake is a rapid development framework for PHP which uses commonly known design patterns like ActiveRecord, Association Data Mapping, Front Controller and MVC. Our primary goal is to provide a structured framework that enables PHP users at all levels to rapidly develop robust web applications, without any loss to flexibility.

Qcodo:
Qcodo is a completely object-oriented framework that takes the best of PHP and provides a truly rapid application development platform. Initial prototypes roll out in minutes instead of hours. The framework consists of two main components: the Code Generator and Qforms. While the framework was designed to support the complexities of large projects, it is an incredibly lightweight framework which can be utilized by small and large web applications alike.

Symfony:
Based on the best practices of web development, thoroughly tried on several active websites, symfony aims to speed up the creation and maintenance of web applications, and to replace the repetitive coding tasks by power, control and pleasure. Symfony is based on several great open-source projects.