I used to do a Best Hand and Headhunter jackpot in my league. Best Hand went to a minimum of a full house using both hole cards. I put the both cards qualifier in later on just because to me it seems like more of a "pure" best hand if you're using both. We had a case where someone played J6 offsuit and ended up with a straight flush to win the jackpot. That kind of behavior shouldn't be rewarded in my mind!

If we had a week where no one qualified (no full houses), the jackpot rolled over to the next game.
Headhunter was similar. If you knocked out the last winner, you won something like $15. If someone won 2 tourneys in a row, they won the entire jackpot. The only time it was won was worth $150 or so.
I stopped doing them this year. Just too much to keep track of and collect. The guys still talk about Best Hand every once in awhile, but it hasn't been a major loss. We thought about bad beat jackpots, too, but again, just too much to have to worry about tracking when I'm trying to play.