Award extra points to answer?
1. Bounties are a great encouragement for us to work around a featured question, giving it extra attention and views. User who posted the accepted answer gets reputation value as set inside the bounty. But sometimes, there may be more answers, which are very helpful and useful, or may be pointing towards accomplishing the same task (done by the accepted answer), but in another way or route. Upvotes are helpful in this case giving them +10 rep. But if someone else found the answer very helpful for him, he may be willing to give the answer more than just +10. In this case, a custom rep feature, that any user who found some answer great, can award to that answer will encourage users more. I GOT THIS in @Bart's answer.
2. It will be fine if this facility is available to the questions also, giving some custom rep to the user who asked question, if someone found the question useful, which led to great answers (only great questions can help develop great answers), more than just an upvote, which gives the user +5.