Adding Menu "Levels"

I ran into a situation a while back where I need to style menu link items differently depending on how far away they were from the menu root item. That is to say, the designer wanted top level links to look a certain way and everything else to look differently.

I solved this immediate problem by overriding some of the menu theming functions: in hook_menu_item I checked to see if a given menu item's parent was “0” (ie whether or not it was a top level item) - if so, bam, I stuck in the "level_1" class – if not, bam, it got "level_2." Ex:

About Us Section
* About Our Staff (class="level_1"...)
** Staff by Department(class="level_2")
** Staff A-Z (class="level_2")
** Depressed Staff (class="level_2")

This approach obviously only addresses two levels of menu items. When my designer comes back with a need to style level three items, I'm hosed.

It would be great (for me) if menu items simply had an out-of-the-box feature that added a class with a delta that was relative to the given menu's root item. I can see how this might require a rather icky recursive set of queries, given the current practice. Maybe that sort of thing has kept such a feature from moving forward. In any case, functionally, this is what I would love to see.

Thanks!