Well, someone from pre-EE days filed a lawsuit against CIC, and this was discussed under the current thread too. Here is the link to that external article:
https://secure.immigration.ca/forum/forum_posts.asp?TID=1191&PN=1&title=delayed-background-check-csis-mandamus
Notable quotes:
'... My lawyer told me that in most of the cases, the moment you sue immigration, the wheels start to move and CIC tries to finalize your file before they have to appear in court. So most likely, you'll get your immigration before the court date. And that was exactly what happened to me ...
In my case, right after I filed my claim, immigration contacted me and asked for my updated address. Then, they started to ask for some documents, etc (including renewing my medicals). After the court date was set, they seemed to double the speed! Long story short, I got my immigration visa shortly after the court date was set (i.e., a few months before the court date). ... '
However, I do not encourage anyone to take this action. The circumstances are different, and CIC may covertly take revenge, which might affect your applications.