mcmmoRankup for mcMMO - Allow your players to auto-rankup based off of mcMMO skill and abilities, plus you can give them rewards for any and all rankups when they take place.  Additionally, allow your players to by-pass the skill features (natural order) of ranking up and let them Buy-a-Rank, plus many, many more options.  Full Administrator/Owner ranking reports, Custom Color Schemes, and more...