Just had a great idea for a minimap mod while watching Chickenbones' wireless redstone videos. A minimap is immensely useful and at this point I won't play without one. The problem is some people find it a little cheaty since you just all of a sudden have superhuman awareness of your surroundings. What if you required the player to craft a glasses type device you wear on the head to access it? You could also place nodes similar to redstone torches in order to set waypoints. Would give it more of an in game GPS feel instead of seeming so cheaty and external.