This can actually be done with the scoreboard mechanic; no plugins needed. I just showed awasted how to quickly set it up in game, so total pvp kills are currently shown above a players head. Initially it looked like the kill count might not be updating properly, but we'll see. Just kill each other and see what happens.
http://dev.bukkit.org/bukkit-plugins/scoreboardstats/ Would this accomplish the desired status'? Forgive me if its not a correct plugin for our server. It does say it might be hardware intensive :/ but maybe it can be tweaked to run a bit leaner? For a stand alone, tukMC hud adds this function(Note it is not server specific and your death count resets everytime you quit the game, but the Kill counts hold true): http://i.imgur.com/0vhE7fk.jpg