I went to the session “Developing Repository Managers for KM” just out of curiosity. I don’t have any plans in that area but because some of my current coding is for the Enterprise Portal I thought it wouldn’t harm.
Presentation and exercises were about concepts of the Repository Manager (RM) for NW04 and an example implementation using functional aspects like namespaces, security and properties. For the exercise one had to implement a RM for Zip files. It was split up into three parts regarding your experience RF and RM so you had to choice to just add some functional parts or implement the whole stuff.
So for me this was mostly for people that needed some guidance for an example implementation. The exercises are available at SDN as well as other further documentation and guides. If you are interested in this topic you’ll find a number of resources.