I found this plugin awile ago and thought it was neat, it's a combination on 60 something different "powers" which in heroes terms, would be assigned passive/usable skills, which you could create your own "class". I was thinking, maybe you could implement some of this plugins ideas into new skills, such as bloodbend, which stuns a target for a short time and steals some of their life. just a thought...
http://dev.bukkit.org/server-mods/s86-powers/
http://dev.bukkit.org/server-mods/s86-powers/