A good thought! Start with the http://www.enworld.org/forum/4e-fan-creations-house-rules/255224-book-npcs-2-0-a.html and it's super easy, too.Another possibility -- note that the Monster Manual gives orc and hobgoblin racial traits. You can create classed NPCs of those races at any level from 1-30, and add templates if you want to make them elites or solo monsters.