The Deltaset Project is a new generation productivity tool (Apache 2.0 Licensed) for extremely fast implementation of a full blown, java based, web applications.
It supports Google Application Engine.
Based on JSF 2.0, using Spring 3.x, Spring Security 3.x, Deltaset will create for you web ui, RESTful web services (JAX-RS), integration with JAXB, JQuery, JQueryUI.
The first known project that supports JSF 2.0 with Expression Language 2.2 on Google Application Engine.
Here is the "Quick Start" : http://dmakariev.blogspot.com/2010/08/extreme-productivity-with-jsf-20-and.html