HUD in other window managers (especially xmonad)
Solution 1:
The problem is your Desktop Environment i.e. Unity, is a plugin of the Window Manager Compiz. Similarly GNOME 3 is a plugin of Mutter.
So thing is that, the menus of your Window Manager are tightly coupled to the Dash of the Desktop Environment, which can be only done via a plugin.
If there were a Unity plugin for Mutter or Kwin or other Window managers, then they could be used too instead of Compiz