I've been doing pieces like these on a regular basis for different conventions and such- no set pattern to them, really, though they're certainly popular enough- they usually don't stay in stock long enough to get photographed.
Your new masks you posted look great. I think this one is my favorite though. I guess I'm a sucker for brass on black. It'd be interesting to see a second piece maybe for the bottom of the face to go with it.
This is a fabulous looking piece: The gold patterns are gorgeous, and the gear eye is damn cool. It's amazing what you're able to do with just leather, paint, and salvaged clockworks.