i actually was thinking about the same type of idea. "Why hasn't anyone made decent naruto mmorpg?" I though lot of ideas for how the game would work. Since you could pretty much use every aspect Naruto in rpg, like chakra types, -levels, Tai-, Gen- and Ninjutsu levels. Missions to earn money, Villages would work like factions, you could choose between bloodlines or be normal....etc,etc...
But then i became realistic and though of my programming, modelling, animating, skinning, mapping skills and gave up the idea...
But do you realise that you cannot profit from making this type of game. You cannot ask anyone to pay for playing it, that would be against the law.