I love the idea of playable Ratmen, mostly because it fits the idea that Velious should have had it's own race like Kunark did. It's possible that there was something thrown about for Velious that we never knew about, as well.
I'm gonna have to disagree with Zuranthium though, talking about playable Centaur is going too far. Mice definitely scurry with bursts of speed when my cats see them
Anyways there have been some efforts to get armor textures showing on mobs like Frogloks, but there is no way in hell anyone would be able to get armor textures looking normally on Centaur.
Edit:
Found the old pics of the experiments.
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