Modding this Nerf Maverick was my very first attempt at any vaguely steampunk accessory. From what I've seen on the interwebs it's a hotly-debated right of passage of some kind. Painted plastic seems to be very frowned upon in the community, but this was a fun project nonetheless.
Some non-working watch bits were glued to the sides (a huge faux pas, I know, but I lack to tools to get rid of the Nerf logos so I had to go with covering them up). Up on top is a cable splitter that I've used as a sort of energy box, with copper wires running back into the gun to power the steam mechanisms inside.
I'm very pleased with it as a first try, even though I think I tried a little too hard!