I like the idea of a bounty for a best answer. It seems like there would need to be an amount of time in the beginning where the answers are compiled, then a second phase where voting occurs. Rather than the OP choosing the winner, the vote could determine the correct answer. You should probably be prevented from voting if you are one of the participants, and the post should show up as a 'new post' upon the beginning of each phase. Each of these two phases would need a time-limit or answer limit and/or vote limit associated with them. These request/bounties will likely get lots of traffic because people will continue to come back to check on it. It would also require notifications to participants so they know where and when to come back after each of the phases are elapsed.