I found black rivets and other hardware on ebay/amazon while putting together a costume for dragoncon, they were pretty cheap. I cheated on the buckles though. Had some brass plated buckles, I sand blasted them, and enamel rattle canned them. Held up great but it was only for 4-5 days of use (still look like the day I painted them). Wouldn't want to risk the wear and tear on a longer project though. Powder coating is pretty durable, would be the way to go, but I dont have an oven yet. If you are trying to color something already in place, it may be pretty tough to pull off.