Well, looks like I have a goal while we wait for the custom buildings fix to get rolled into the formal pack. It looks like Naga are coming along at a crazy, awesome pace, so I think I'll hit them next and probably pick up Spawn of Holistic along the way since sticking a jagged maw in the middle of a dwarf's chest with the odd tentacle sticking out of various orifices shouldn't be too rough. (Though now I feel a little weird for saying that).
As for the Naga, it looks like four main castes from what I understand. A brutish warrior caste, a nimble hunting caste, a general worker caste and a witch/caster caste. Kind of figured to go with the reptilian/aquatic-looking versions for the warrior and hunter castes (the males) and use the more traditional half human Naga version for the general worker and witch/caster castes. It should keep it a little easier to pick out which ones are which at a glance if I can give them slightly different body shapes.
Here's what I have as a concept for the hunter caste, cleaned up somewhat from my original posting since it downscaled awfully and looked really, really, bad even for my limited drawing skills. I still need to split the sprite so I can allow the right hand weapon show up behind the head and there are no eyes (they're a different index), but it's a start anyway.
Edit:
I went ahead and put together bases for the other castes and added them to the spoiler below. Thinking I might redo the hunter one though, it is still a bit too muddled for my liking. I did use part of the x128 human female sprite from the human sheet to keep them consistent with what was already there. Should be able to combine the witch/worker sheet pretty easily this way and cut out one *.png anyway. Still need to reposition some arms on the male castes to be sure they wield properly and do something about separating the heads from the rest of the base sprite so they can be a different index. Will probably give the worker/witch castes different head sprites to make them more visually diverse.