Thanks for the elephant sample, that should be enough of a test case to get things working correctly.
I'll have to decline putting this on github for now since I don't use github. If you want a link to the plugin this is where I'll keep a working download: plugin-creature2d_t165057
Thanks for the technical help too, but it shouldn't be necessary. Between the source code, the documentation, and existing examples it looks like I've got everything I'll need.