Nav Sub Links - with a menu


What would be my best bet (or is there an existing plugin) for achieving custom nav tabs, but more importantly, sub nav tabs with a drop down option

This is basically what i want to achieve

Each forum might have its own menu, and in those menu options, they might need a sub menu. They key is i want to use xenforo's responsive design, but i couldn't create a second "navigation" tab since all the code references id's and not classes

Any help?