Any utility that shows thumbnails of the desktop?

Granted, some pagers could give you a thumbnail but with boxes
representing the individual windows that are open. A few more can
display the icons.

Can any standalone app do this? There is a pager in Enlightenment but
its coupled with enlightenment itself. I am waiting for e17 to catch
up with it (there is no high-quality snapshot in its pager ATM), but
maybe somewhere out there, is a little-known app that does something
similarly?

.