Microsoft Patterns & Practices released the Composite Application Guidance for WPF, a library for creating composite, line of business WPF applications using proven practices.
Per the website:
"The Composite Application Guidance for WPF is designed to help you more easily build enterprise-level Windows Presentation Foundation (WPF) client applications. This guidance will help you design and build flexible composite WPF client applications—composite applications use loosely coupled, independently evolvable pieces that work together in the overall application.
The Composite Application Guidance for WPF can help you split the development of your WPF client application across multiple development teams. In this type of application, each team is responsible for the development of different pieces of the application, which are seamlessly composed together. The guidance includes a reference implementation, reusable library code (named the Composite Application Library), documentation, QuickStart tutorials, and hands-on labs."
Microsoft Patterns & Practices provided documentation, a Stock Trader Reference Implementation, quickstart tutorials and samples, as well as the Composite Application Library itself with the Composite Application Guidance for WPF:
- Stock Trader Reference Implementation (Stock Trader RI) - This is a sample composite application that is based on a real-world scenario. This intentionally incomplete application illustrates the Composite Application baseline architecture. This is a good reference to see how many of the challenges are addressed by this guidance when building composite applications.
- Composite Application Library source code - Developers can use the Composite Application Library to develop WPF applications that are composed of independent and collaborating modules. The library includes extensions to support the integration of the Unity Application Block.
- QuickStarts - These include the source code for several small, focused applications that illustrate user interface (UI) composition, dynamic modularity, commanding, and event aggregation. The Hello World QuickStart provides a step-by-step hands-on lab to create your first application using the Composite Application Library.
- Documentation - This includes the architectural overview, Stock Trader RI overview, design and technical concepts for composite applications, applied patterns, how-to topics, QuickStarts overviews, and deployment topics. Much of this guidance is applicable even if you are not using the Composite Application Library, but you want to know best practices for creating composite applications.

Check out the landing page on MSDN.