While sitting in history class studying WWII, an idea popped into my head. I'd take it for myself, but I don't want to scrap my hack, as it's coming along pretty well.
It would be interesting to make a Pokemon hack based on war. The main character is a soldier for their army, almost all of the enemy trainers are soldiers and leaders of the enemy army/government, and instead of badges you have medals of honor (you could give them all different names and appearances, ie Iron Cross, Purple Heart, etc) and instead of leaders/the pokemon league, you face enemy generals and eventually the dictator of the enemy government. There are only a few towns, and instead you visit many military camps, complete with a medic's tent and supply station. It'd be incredibly easy to take this base and weave it into an intricate story of politics, full of betrayals and the like.