I was playing Ice Wind Dale II over the weekend, and was impressed with some of the possible skills and feats that were offered. For example, they offered "magocracy" and "merchant" feats, which got me thinking that I'd like to see that notion developed more -- the idea of having classes (or at least prestige classes) based on more Rennaissance-aged classes: merchants, politicians, patricians. You could develop special skills, feats, and other achievements for such classes. Depending on how comprehensive it got, it might support a book or even part of a campaign world that is set, perhaps, 100-200 years beyond the archetypical "medieval" setting of D & D.