I really want to see these options in game..
Techhair: Artificial hair with properties similar to synthskin. Tech hair can be any color, can emit light like light tattoos, or change tension (so you could make it stand straight up when you are angry, for example). It can completely replace your real hair or be added to real hair (like a weave). (And yes, it can also be used on any part of the body)
Synthskins: These are an upgrade from Chemskins. They are actually embedded into the real skin and contain a display layer that can emit light and patterns. Synthskins can display a number of special effects.
Turn-On Nails: Fake nails with properties similar to synthskin.
Nails are also important, since we will always see our hand, I hope to see many options..