No intention to offend you, but I can't understand how you can work on mods for Civ4 a whole week before it's released (and no less than a fortnight for it to arrive at your/my country). The most I can think you can do at the moment is trying to get Poser models to look the most similar to the original heads (which I still strongly dislike). Even doing that, you wouldn't be sure whether they'd work in the game or not.
I dunno... I'm just waiting for it to arrive to make any final judgement upon it, but even after it arrives, I won't be getting it for a month or two. In the meanwhile, yes, I'm working on some Civ3 stuff (still have a lot of stuff pending), but I wouldn't even think of attempting any Civ4 art yet (and perhaps I never will anyway)