Because none exist.
so far I've attempted two custom models but got stopped with blender errors.
Well, that's a bummer.
I have my doubts now. I know how to design, model and animate but I'm just starting to learn this modding business. I went through numerous tutorials and read almost every relevant post here on Civfanatics about modding. I don't anticipate any major problems with creating new civ except importing 3d leader was a bit of a mystery.. now I know why. Because it has never been done.
The thing is this takes a lot of time and my time is somehow limited so I'll have to think about it a bit more. My programming skills are intermediate at best so I don't think I'm going to discover anything new.
We'll see how things unfold.
Another random question.. if we have to use existing model animations does this include mouth movement?