If a user has been put on more than 50 people's ignore list, ban them. A reason has to be stated why they were placed on ignore in the first place together with proof to stop abuse.
Sig whores are disallowed having sigs. See how much they post then.
As a board owner, I hate the thought of having to implement any of the systems suggested by anyone including myself, and know that there's a 99% likelihood that nothing at all will change here.