If someone can do something remotely like this: http://www.youtube.com/watch?v=aohtxgH5yHk with a plug in i'd be instantly on top of it. To describe the video that's the Mo' creatures mod for single player. Basically the creator made more creatures and items and some of it is amazing. For instance birds that chase seeds players can drop, tamable horses and saddles, bears that kill other mobs, lions, wolves, Ogres that destroy blocks, and Werewolves that transform at night. So not that I think it should be copied but something that adds more creatures would be great. Not even sure that's possible on the plug in side yet.