Eric: Not by default but you can bind a hotkey to any menu item via Tools -> Customize -> Keyboard.
Type "autohi" into the "Show commands containing" field and you'll see the one you want, Window.AutoHideAll.
Off topic:
Anyone know a way to stop Visual Studio re-indenting the current line when a : character is typed into a C++ file (e.g. as part of a ternary operator)?
The behaviour has annoyed me for about a decade now. :)
I'm not even sure why the editor thinks it should re-indent the line when : is typed (maybe initializer lists?), especially when it's typed after load of other character.