I am a newbie to :) I have only hade LS in less then a week. But I think that I have what you are looking for :)

In my LiteStep\Personal\Hotkey.rc file I have a line that goes like this.

*hotkey win b !toggleall

I hope that it should work for you to :D

So when you press the windows button + b everything should be hidden.

I hope it works for you to....