I actually kicked this idea around too a while ago---I considered attempting a latex mask by doing up a paper pep model, coating it with latex, then peeling the paper away from the inside to leave a latex mask.
Ultimately, I rejected the idea because the outer surface of the latex wouldn't be textured and probably wouldn't look so great. I couldn't think of any good way to add a texture to the outside surface (pressing some sort of textured leather onto it as it dried, maybe?)