I would say instead of just focusing on the vagina model, focus on a unified body that has blend shape data that will allow if to be customized to be any body type. This would include customizing the vagina as the model could be design to have adjustable labia length and thickness, labia wrinkles, clitoris sizes, and over all shape. This would be the best way to implement a highly detailed female genitals model that can efficiently make any type of woman you want.

Think DAZ genesis or genesis 2. One body that can be customized to your tastes with a highly detailed genitals area that can also be customized to your tastes or all can be randomly generated thus adding variety.

Thoughts?

P/S this is not impossible to implement nor is it even that difficult....

I forgot where he says it, but Xpadmin mentioned somwhere on this forum that they plan on releasing a rigged blank slate type of model specifically for modding. That model will have all the parts they use in game so you can customize that or use it as a guide for what your designing.