Just spotted the following on Visual Basic Developer Center - I know a lot of folks at the community events have said they found applications blocks like these helpful in the past... so just in case you haven't spotted this new one...

The patterns & practices group has released the Composite UI Application Block - a reusable, source code-based component based on the Microsoft .NET Framework 2.0. Build complex, smart-client user interfaces based on well-known design patterns such as the Composite pattern, in which simple user interface parts can be combined to create complex solutions, but at the same time allowing these parts to be independently developed, tested, and deployed.