Ady, I think it would actually be really cool if you took the layout of this Starkiller action figure, and added a Vader Mask to it. That way, it's just enough Vader added in, without going over the top. It would also mesh better with the PT, since the Vader outfit would look a little off next to the PT Trooper outfits, since it was designed to be similar to the original Stormtrooper outfits.
Perhaps something like this (sorry for my AWFUL photo editing skills):
