Something like 'KDE Present Windows' / 'Compiz Scale' / 'Mac OS X exposé' in Openbox / LXDE / Xfce?

Is there a DE-independent utility to show all windows beside each other in more lightweight DEs like Openbox, LXDE or Xfce?

Something like this:

How about Skippy-XD? It is a full-screen task-switcher for X11 similar to Mac OS X's Exposé feature.

From the above site:

Skippy-XD is a standalone application for providing a window picker with live previews (including live video) on Linux desktops that run an X server with compositing support. That means it's not baked into the window manager, and the compositing is not being used all the time. So the performance of you're window manager isn't degraded, but you still get a window picker that's every bit as pretty as OSX's Exposé or KWin's "Present Windows", with all the desktop-navigational efficiency. Compositing only takes effect when you press the hotkey to display the window picker.

I've tried it and it works well, though it doesn't include window decorations.

To install latest development packages (recommended), use the Skippy-XD PPA (daily). If you use Xfce, you can easily bind skippy-xd command to Alt + Tab or Alt + Esc in Settings > Keyboard > Shortcuts. For other DEs it should work similarly.

Binding Skippy-XD to a screen corner

You can use xdotool to bind skippy-xd to a screen corner. First, make sure xdotool is installed:

sudo apt-get install xdotool

Add the following line to your autostart applications:

xdotool behave_screen_edge bottom-right exec skippy-xd

Valid location keys are:

left
top-left
top
top-right
right
bottom-left
bottom
bottom-right

xdotool is very lightweight and should have next to no negative impact on your system.

Source for the screen corner binding technique:

http://urukrama.wordpress.com/2008/05/23/expose-type-behaviour-in-openbox/#comment-13674