I would like to see a plugin which would select at random one player in the game and set a bounty on him. Instead of something like money though, I would like to make it so that killing him would get you an extra level. The player who has the bounty on him should change at the beginning of every round (Should probably change on death of previous bounty player if deathmatch or elimination is enabled). Obviously it shouldn't allow someone to get past nade or knife level.
Things you should be able to set:
How many players need to be in the server before the plugin starts picking people.
Just one player, or one player on both teams.
How many levels the player who gets the kill should be given.
Some sort of visual clue as to who the player is, probably just color based. The clue should not make it difficult to tell which team the player is on to avoid team killing.
Things it would be nice to be able to set:
Only get the bounty if you are the only player to injure the player with the bounty on him.
Only get the bounty if you knife the player.
A different number of levels based on whether you shot or knifed him for the kill (Would need to disable only getting the bounty for knifing the player).