Have ya'll checked out the DNN (DotNetNuke) system? I wrote my own CMS based off of the IBUYSpy portal and ran it for for the last couple of years until I finaly decided to stop being stubern about the DNN system being written in VB instead of C#. With
the amount of poeple working on this open source project it has turned out to be be quite impressive.
If nothing else it is a very good reference guide to what you can do with SQL, .Net, and XML. The skinns allow for a very versital layout and adding updates are a snap.
Whether your looking at a solutoin that will fit your project or just looking for a reference this is a must have project to go over. Not to mention you will find a lot of help from the developer comunity on it.