Feather/Moire Hair Color (Or Scene Girl Hair)

After seeing the end bits of this video, I HAD to try doing something like that. My teacher thinks it was airbrushed on with a stencil.

Here are some of my tries. I experimented with a variety of different application techniques, and draped the wefts across my lovely assistant to grab some photos. :D

How would you do something like this? Leave me your ideas in the comments!!