Yeah thats one thing I like about the other major DN forum, you can search for *.ca and get a list of all .ca related threads. I think the rewrite solves a lot of that. I would like to +1 the .ca Wanted section proposal, if you look through the discussion section for .ca's previously people were using it for their wanted topics as it targets the readers better. Idealy would be best to have the topics posted in the main Wanted section and a mirror placed in a .ca wanted section.
To implement it would be fairly straight forward, on new post in the wanted section check the body and title for .ca match, if successful create a link topic in .ca Wanted section... could get tricky with people posting other extensions taken though