UPDATE: Added the presentation to download below.
I found through a blog post of Greg Duncan a site (Research channel) that has a video of 3 hours on how to design class libraries in .net.

“Produced: January 22, 2007

Description:
This class presents best practices for designing frameworks that are reusable
object-oriented libraries. The guidelines are applicable to frameworks
ranging in size and in their scale of reuse from large system
frameworks to small components shared among several applications. They
started as a small set of naming and design conventions, but have been
enhanced, scrutinized, and refined to a point where they are generally
considered the canonical way to design frameworks at Microsoft. They
carry the experience and cumulative wisdom of thousands of developer
hours, over three versions of the .NET Framework.

Speaker(s):
Krzysztof Cwalina, program manager, .NET Framework Team, Microsoft

Runtime:03:40:56″ [Description leached in full]

Sadly enough I didn’t see any possibility to download the video so I could watch on the train on my way home…

Download here: http://suddenelfilio.net/cwalina/14050.asf [461 MB] (I hope I’m not braeaking any copyright rules)

Source: The ResearchChannel – http://www.researchchannel.org/prog/displayevent.aspx?rID=11087&fID=2740