Carl,
I am just going to work on this in my free time, no client is driving it. I just know it is an important site-wide tool and I really want to see it done right.
It looks like those categories are all tree structures and should be able to be modeled with the system Neophytos proposed.
Hopefully we can develop a flexible data model that can start out with a simple user interface and could expand to meet more of the requirements in Peter's package.
An important key is to allow all packages to tie into the system so that data and pages can be found by category. This information could also be used to enhance search.
