http://blogs.msdn.com/bclteam/archive/2006/04/10/571096.aspx
They talk about how CodeDom is used in the designers for 2.0
There are also several comments and responces complaining about some of the short comings people have with the CodeDom. Some of these short comings are refuted with work arounds. Including a short coming that I have often complained about. :)