There is No issue having Wicd in the systray for unity-3d in 11.10, the methods as described in the linked answers work fine, ie 'add to systray whitelist'
As far as in unity-2d it can work but -
you need an updated unity-2d, the Daily-build ppa has one for 11.10
https://launchpad.net/~unity-2d-team/+archive/unity-2d-daily
Then you need to edit the whitelist to just 'all'
Related bug report
https://bugs.launchpad.net/unity-2d/+bug/847525
While having to use 'all' instead of individually specifying is a less than ideal solution, atm for unity-2d it does work as expected
Attaching screens for unity-2d, (Wicd & vlc in systray) & unity-3d (Wicd in systray
unity-2d* (5.2-0ubuntu1~bzr806); unity-3d (shows in both current 4.24 & proposed 4.28