Lets just say that it will be a while in development. I am trying to implement the Composite Application blocks for WPF from Microsoft in an attempt to make the application more modular. I will be updating and releasing under the v2.0 CTP version and I have uploaded the installation files. This is a ClickOnce application, so you will always have the latest version of the CTP.
The current version CTP1 has only those changes to allow for the new Navigation and structure options, but More features are on the way.