I based a prototype application on the DirectoryLookupModularity (http://www.global-webnet.net/blogengine/category/Prototype.aspx)
which cost me a few hours of head-banging time - particularly when I tried to add a StaticResource for a new template I created. Neither the Shell, nor any module, would except a static resource unless it was in the UserControl.Resources!
I had actually searched for this StaticResource odd-ball behavior in this forum with no luck so perhaps this message will help the next person that bases a prototype off of this sample...
The problem: the App.xaml.cs code-behind file was launching the bootstrapper from the Constructor - not the OnStartup() method; this oversite doesn't permit you to use StaticResource during load - so you have to use DynamicResource.
Just downloaded PRISM 4 Drop 2. Although I've been a hardcore Unity cronie since its conception I must admit I like what I'm seeing - my MVPVM prototype (above link) is in the process of being ported over....