The PfaBB portal system (which is basically an add on to YaBB, if you're not aware) has a menu preferences area in the Admin center that allows you to add or remove items/links from the menu.
I also just wrote a mod that completely revamped/redesigned all of the menu code and now allows for the item separator's to be changed, add custom separator's anywhere in the menu and the ability to create as many separate menus as you want for your site. When creating a new menu, you give it a name and then the name is turned into a new yabb tag that can be used anywhere in your template.php file or, in Pfabb's case, in any block on the site.
If you are looking to do stuff like that, you may want to consider using a portal like Pfabb or if there are enough people interested in a feature like this for Yabb, I could probably convert my mod to work with Yabb, but that seems to lean toward portal type options.
Check out Pfabb here:
http://pfabb.lunabyte.comCheck out my mod here:
http://pfabb.lunabyte.com/index.php?board=8;action=display;threadid=654