Scott has a great post about the things he learned while creating his first Silverlight control.  He’s been writing Flex apps for quite some time so this article approaches the problem from the Flex developer’s point of view.

Reading this post its clear that while the custom control model we have now is a good start, but there's definitely things we can do to refine this before v1.1 ships as well as putting together a great tooling story for both custom control creation as well as custom control consumption into Silverlight projects.