Check the site I mentioned. They talk about catfolk and where in D&D they'd come from. Again, not a lot of people seem to like them, but D&D seems to have entirely too many (insert random animal)folk already. Catfolk are particularily overdone. I do know that there's a stat block for the Lord of Cats in the Epic Level Handbook, who is a Faerun demigod, and I'm pretty sure there are indeed catfolk in Faerun as the thread I linked to suggests.