The main challenge here was to include a very thick navigational structure in a clear, visual way. Using color-coded sections and a tabbed sub-section navigation, I think we achieved this goal.

You'll note four levels of navigation shown on the first screenshot. Two on the top, a third down the left-hand side, and then a fourth at the bottom. I was especially pleased with being able to keep track of where you are in a site this deep in such a clear way.