I love it! Nice job. I know next to nothing about steampunk, but from hat I do know you hit the nail on the head. Definitely post any other headphones you might mod like that on here.
What source and amp do you run them out of? Does vinyl count as steampunk? If so, get a turntable if you don't already have one. The music sounds better, is more fun, and there is something very cool about it. I am sure you could find a vintage TT that looks like what you want, but getting to sound decent is another challenge. I guess you could mod a TT, though that sounds much harder than a headphone. Anyway, good luck and massive kudos.