I think part of the problem here is that when you post a list of unicorns even the people who DO have them don't have multiples and are hesitant to pass them out. And then when the same people have unicorn lists over and over those that have them are not going to keep sending them to the same person.
I think all lists should have a mix of HTFs and just plain favorites or never hads.
This would keep the thread moving and if you get a unicorn then so be it. Some people tend to pick up the "easy" lists over and over and their wants are almost impossible to cover.
There, I p00ped in the wheaties...