I'm looking forward to emulate the behavior of OS X Dock Stacks so that I can have, for instance, one stack for browsers and another one for IDES. People at ask ubuntu are doing a lot of cleaver stuff with custom Launchers and Quicklists (see What Custom Launchers and Unity Quicklists are available?). So has anyone figured out how to have stacks in Unity? Anything fancier than a static Quicklist over a dummy folder icon?
Give a try to Cairo Dock, whose interface is easy to set up as you wish and its gadgets includes stacking with several fancy features.
Screenshot from my Desktop:
More screenshots from the net:
Parabolic style sub-dock:
Dock over dock style
Slide style sub-dock
Rainbow style sub-dock
Sorry, I forgot to mention the Panel Mode, which is cool, an illustration is placed here:
Check out Drawers.
You can put just about anything in a drawer by drag and drop. You can even nest drawers inside one another. See below for a screenshot. It's been submitted to the software center but is awaiting review.
In the meantime, to install drawers run the following in a terminal:
sudo add-apt-repository ppa:ian-berke/ppa-drawers sudo apt-get update sudo apt-get install drawers
Then create your first drawer by opening the dash and typing Drawers.