It's not hard to find 10 zealots on SO. 100 would be better or set an exponential threshold related to the upvotes and views.
I like the 'exponential threshold' idea ... if for nothing more than the new sport it would create. Geeks would have to convince a LOT of people in order to close certain questions.
It might even introduce new terminology: "The chances that this question will stay open forever are approaching infinity..."