Here's a few pics of a mask I have recently started for one of the guys in the Emerald Garrison.
Jedi Master Plo Kloon.
It is being built on a generic sized head so it should fit most.
Haven't quite decided on the final casting yet, might go silicone or foam latex.
The mouth piece is done in bronze resin with a fan and mic fitted. This will be mounted on seperate head straps that go under the mask. This should help make it more 'troopable' ie. you will be able to remove it. The eye pieces will also be finished in the same material.
Pics are off an Iphone so they're a bit shoddy. I'll take some better ones next week.