In OS X 10.9 Mavericks a smart folder (or a saved search) dragged to the Dock behaves like a folder (smart folders by default are saved under ~/Library/Saved Searches). Right click gives sorting, display and viewing options similar to ordinary folders dragged to the Dock. A drawer icon is shown if Display as Folder option is selected. In grid view Quick Look works, too.

I did not check if it works under 10.8 or 10.7. I have to mention that there was already a hint about how to add ‘recent things’ stack to the Dock.

[crarko adds: I tested this, and it works as described.]

Source: Mac OSX Hints