Multilevel Sub Menu for Twitter Bootstrap Project

As you may know, with twitter bootstrap release version 3.x, there is no support Multilevel Sub Menu anymore in navbar and dropdown. So as an alternative which is better than you tweak twitter bootstrap by your hand, you can use "SmartMenus for JQuery" which can use side by side with twitter bootstrap and it is Responsive and also Free too.
Check out SmartMenus in it homepage http://www.smartmenus.org/