The Patterns & Practices team has recently released the Composite Application Guidance for WPF which provides guidance for "componetizing" the development of enterprise-class WPF applications across multiple development teams, with each team owning a piece of the application, and then seamlessly integrating these pieces into one homogenous application.
Included in the guidance package is a reference implementation of WPF application, CFI Stock Trader, that models this guidance, reusable library code (called the Composite Application Library), documentation, quick start tutorials and hands-on labs.
You can download the bits here or to learn more about what the guidance entails, head on over to the developer center on MSDN.
I can't wait to try this stuff out!