In cinema, it's the renderers that do the hair and even the physics for how the hair moves in animation. Pixar's Renderman, for one. I nearly fell over when I looked at the price of Renderman recently - because they've reduced it to about $500. Which is really, really cheap for that app. It won't be super fast, because the cinema guys use render farms, lotsa CPUs at work together (each with a $500 seat...), but yeah, plausible hair.