Could timestamps of bounty activity be added to a question's revision history? Or something that would show the bounty events for a question anyway? Obviously the revision entries would need to be immune to rollbacks. I think this would help to clear up some of the questions that get asked related to how bounties were or weren't awarded.
Or, could they even be added to the question page itself so that you didn't have to visit the revision to see it? That might make more sense, especially for users who don't make it a habit to view the revision history.
At the risk of asking too much, since it looks like this suggestion's going to happen :) (thanks!!)
Something else I just thought of is that it would be nice to also have a flag shown on answers that do not qualify for the bounty. ie- Answers posted (and not edited) prior to the bounty being set get something visible indicating they don't currently qualify. I know that's extra logic, so I'm happy with just the indication of bounty events.