Creating steampunk jewelry may be your best bet. Other items the guys like would be goggles, and modifying Nerf guns for a steampunk look. Unfortunately, the gun mods would call for spray paint and that would be an outside project. Not sure how much time or money you have, but buying the goggles to modify could be costly.
As for the jewelry, you can find steampunk elements, gears, etc. in Hobby Lobby or Michaels stores if those are near you. You could also throw in hardware store items like washers, O rings, hex nuts in brass and zinc.
Here are a few links that might get you started:
Easy steampunk necklace you can recreate with a metal shape you can distress and hang with charm such as gears, keys, hardware element. A simple leather cord would be good for girls or guys.
http://bfscrafts.blogspot.com/2012/08/easy-steam-punk-necklace.htmlAnother simple necklace example using hardware washer.
http://dollarstorecrafts.com/2010/06/make-a-steampunk-pocketwatch-pendant/Here are some examples from fellow craftsters:
http://www.craftster.org/forum/index.php?topic=349575.0Another example of a steampunk necklace with gears. All these elements can be found in the scrapbooking area of Hobby Lobby or Michaels, the designer is Tim Holtz.
http://nbetween.deviantart.com/art/Steampunk-Necklace-309408110Let me know if you have any more questions, I love steampunk!
Lisa