LawBot has one cool example of a styled ChildWindow, including a styled Accordion.
The Silverlight 3 ChildWindow is not very attractive. So I decided to design it with some styling. I also
styled a Silverlight 3 Toolkit Accordion Control. Both I put together
and made an upload to the Expression Gallery as a full sourcecode
example, licensed under Creative Commons.
Especially
the sourcecode of the Accordion styling might be truly helpful for your
own styling adventures. And in fact: Styling a Silverlight 3 Toolkit
Accordion Control is really an adventure.