One apartment I lived in was rented out by a private landlord, and there we had the option to write a personal letter/application which would allow us to skip the queue if we matched what they were looking for. We had just become a family of three and they wanted more families with children so we were approved. That was completely voluntary though. In honesty, I think it's kind of weird that we could jump the queue but we were no longer allowed to live in my student apartment so we jumped on it.