Provider Based Features
Found a nice newish article on MSDN about creating provider like features, not just extending them.
"The ASP.NET provider-based features rely on a common set of public types and helper classes. Stefan Schackow shows how to author your own provider-based features by leveraging the provider model support in the .NET Framework 2.0 to quickly and easily build a pluggable and extensible provider layer."
Althouh it's true that the provider toolkit gives great samples on extending and working with the providers, this article focuses on a provider from start to finish. While also providing a clean, nice Provider Template you can use in VS 2005.
Article and Presentation by Stefan Schackow
Code Template for Provider Based Feature