Are you referring to the list of channels you get when you do /list
or do you mean the Favorites list?
If the first, customization can be done via a script, if the 2nd, I can't see how much more customized that can be made, as it's already designed to handle just the channels the user puts into it.
If I've missed the list you're actually referring to, please post how you currently get the list, so that I'm able to duplicate the commands in order to see the list you're referring to.