D'oh! Right answer to the wrong question...sorry about that.
I believe the file yo uare looking for is one of these:
willk@penguin1:~$ locate .menu
I checked one of these and it seemed to have the layout of my menu. I could be wrong, but check here: http://people.fruitsalad.org/phil/kd.../kde-menu.html
There are some cool details about how the whole menu system works and may help with your question.