Cairo Dock (also known as GLX-Dock) 2.2.0 will be a truly amazing release. After announcing a new autohide option, a new systray and the MeMenu applet, a new video with a feature to be released in Cairo Dock 2.2.0 was published on YouTube by the Cairo Dock developers: multiple Cairo Dock instances, each with its own settings:
All these new features are already available in Cairo Dock 2.2.0 beta which can be installed in Ubuntu via Cairo Dock's weekly PPA (warning: it's unstable):
sudo add-apt-repository ppa:cairo-dock-team/weekly
sudo apt-get update && sudo apt-get install cairo-dock cairo-dock-plug-ins