Thanks, Karen. Sorry I wasn't clear. I meant the Advanced Search page mostly. We can live with the navigation on the public page as is but to make the Advanced Search easier for visitors it would really help us to be able to configure the number of category windows.
As it is, if an inexperienced user - and most of our visitors aren't particularly computer literate - used the advanced search page we doubt they would figure out they can select multiple items from the category list, especially with so long a scroll, they might not even figure that part out. Writing out full instructions on the page is not an optimal solution for us..
We already have a tree structure like you describe. We have a "Topics" main category with children and the occasional grand child all together at the top of the list and "Places" as a main category with children below the "Topics" list.
But your answer actually touches on what we wanted to do on the public pages. I just haven't figured out how to have the knowledgebase Left menu format get dropped in to the left sidebar of our wrapper along with our other links.. I managed to tell the knowledgebase to use our wrapper. So now I have to format the page to accommodate the knowledgebase layout and see how I might use your menu format.
The Admin area we won't change in any way.