Steampunk is teh awesome
I've dressed up as an Audiologist before- my partner went as a photographer- or as he put it, 'an Image Chronicler'- see my profile if you want a peek lol XD.
I had a blast making bit and parts for my stereo speakers and so on, and although ours was still pretty tame [we had to go representing a radio show] it is a total blast to dress up steampunk, you'll have alot of fun!
Other than 'image chronicler' and audiologist, some ideas that we had were:
-Runner boy/girl [or Steamboy/Steamgirl]:
Picture dirtied and ripped trousers, a big messenger bag, goggles, and big boots. Big gloves for carrying things, and an emblem on a vest or something to represent the company you work for.
Pretty easy to picture- messy hair and dirt on face, big brown overalls, rags in the pockets, big gloves, bunches of gears on a chain as a sling bag, a wrench, tools....
Airplane cap, goggles, and slings of gun ammunition. Big guns. Lots of weapons strapped on. First line of hired defense.
Think upper class, posh kinda dude/dudette. Pants and a suit, gears everywhere, gold monocle. For the girl, a dress with gold gears and weapons hidden up the sleeves.
Hey, even mudane jobs can sound cool if you give em good names and costumes.
Best of luck