Why dost thou vex me so?
It's not too bad, but available documentation is awful. And I'd forgotten that you have to use weird tools to turn your model and animations into a usable .mdl file. Apparently id Software exported each frame of animation into a separate file and then used a custom tool to assemble those into a Quake .mdl file.
Think I'm gonna just roll my own model format and use that for my game instead. Looked into it, and writing a custom exporter for Blender looks ridiculously easy. And I can still be lazy and do vertex animation in the game instead of bones, since Blender will happily give you the transformed vertices for each frame of animation.