You can put logic in the routine that builds the menu to filter based on Customer Level. Or you can put logic in the MasterPageBase to remove all category menu items that have no children and then just use Customer Level to filter the individual products, which would then result in some empty categories that you could remove.
The second option would allow a great deal of future flexibility without having to constantly modify code based on new Customer Levels being added.
ML9.3.1.1
SQL 2012 Express
VS 2010
Azure VM