There's a Nov 6 symposium about "The Role of Interveners in Public Interest Litigation" at the U of Toronto http://www.aspercentre.ca/events/calendar/interventions.htm You can get the program and links to a few papers from this page, in case anyone's interested.

One organization (ARCH) and two individuals (Joe Arvay, Mary Eberts) who have been involved in ABA litigation are part of this symposium.

One of the symposium papers reports that between 2000 and 2008, only a tiny proportion of interveners granted leave at the Supreme Court of Canada (less than 3%) has been individual interveners. Individual interventions have also been more likely to be denied by the Court than interventions of any other kind.