Since release 184.108.40.206 of XWindows Dock, you can put animated gif file directly on the dock. But you can also replace any icon on the dock with an animated gif! In the case of an app (exe file), the image is animated only when the app is running...
You can found a lot of animated gif on internet. I join two of these here to demonstrate the use with XWindows Dock.
Hope you enjoy this feature.
Edited by Filandre1, 25 December 2012 - 06:47 AM.