This cool feature was first told to be included in 10.10. According to this answer, they were postponed to 11.04, but it turned out they have not appeared there. Now we are after feature freeze for 11.10, and still there is no sign of them. So what's up with them?
I haven't heard a word about them for a long time. Is this idea abandoned? Note it was initially the reason for moving the window-ops buttons to the left corner. Or maybe they are under heavy development and soon will be included in 12.04?
I haven't heard anything about Windicators since I answered that last question. I admit I'm not everywhere and I don't see everything but I'd have expected to have seen something if development was ongoing.
The problem with them is they'd be a complete nightmare to implement just to do half the things Mark was hoping they would... Especially if you want to do that in a nice, standard way that works for all applications.
The effort is far better spent on making Unity good.
I consider Windicators abandoned -- but I'm not in charge of anything :) They may well get pulled up later on but I can't say if or when that'll happen.