I noticed that in the stats section, DUI has an options tab and does all sorts of cool things. I know it didn't add that tab, only changed it, but isn't it possible to remove tabs and such, too? Reason I ask is that I think it would most wicked if the world map tab could be removed (or replaced with something else) and force the player to buy maps. For example, you're in a pawn shop and find a ruffled map of the Bravil area. It's got some interesting paths and notes marked on it, that aren't on your map. I think it would be cool because aside from the maps that would come with the mod, people could make standalone mods that adds a topography to a town that sells new and used maps (marked by differences in price and some used maps would be rather expensive due to unusual information) for the player to take advantage of.
Something a bit like the maps Morrowind had, too. Morrowind's world map had a bit less detail (to my eyes) and I really liked having the road and local maps that floated around. Having a generic pencil scribbled map of Cyrodiil (showing only the cities and main roads) would be really necessary, if this could be applied.
Just a thought, of course. And none of this is relevant unless it's possible to remove/disable tabs.