New Post: Creating a multple window app like Outlook

Sorry, but I never got a notification that you responded. DO NOT use two bootstrappers. You would simply use scoped regions, and use a dialog service to show your multiple windows.

Here is a version of IG Outlook that is more complete with the functionality you are looking for:

http://www.infragistics.com/sample-applications/infragistics-wpf-igoutlook

You can download the source code form here:

http://www.infragistics.com/samples/wpf/application-samples

I hope this helps.