I know there has been a lot of discussion on this, but I haven't seen the solution I am presenting now before (despite searching).
There are many questions that either have a good answer that has not been accepted, or the incorrect answer was accepted.
I propose that a system be set up like the 'vote to close' feature. If multiple users with high reputation vote to accept a (different) answer, it is accepted. Of course, it can be voted on to un-accept the answer too.