Not that it needed reinforcing, but just in case, let's take a moment to geek out at Weta Workshop's creations for Ghost in the Shell.
Weta showed off some of the animatronics behind the geisha robots in a video with Adam Savage recently, with Weta co-founder Sir Richard Taylor explaining the mechanics of how it all worked.
According to Sir Taylor, a young Japanese actor called Rila Fukushima (whose role in Ghost in the Shell isn't known, yet) as a model for the hard masks. Her face was then scanned, hardcast, and that was used as a base for building a hard mask that could fit over the heads of other actors.
The stuff Weta produces is always fascinating, but then there's the animatronics to consider as well. The video's below so you can watch it for yourself, but take a moment - rewind if you need to - to appreciate how ridiculously intricate the work is. And now think of how many masks, how many creations have to be made for an entire film.
For what it's worth, do a tour the Weta Workshop cave if you ever get a chance. (It's included as part of those Lord of the Rings location tours, if you find yourself on one of those.)