We have questions where the OP has commented "Yes, that's it!" or something similar, especially in identify-this-game and then disappeared into the ether.
We have other questions where the consensus is that the answer is correct but again the OP has vanished.
Could we have a new power to mark the question as accepted? Or is there a more appropriate way around this (copy the answers to a new question marked community wiki and hit the accept?)
Just annoying to look down a list of "unanswered" questions when you check you find out they're not.
I was thinking about something like the 5 votes it takes to close, this would also be a community consensus approach.