Here's my first attempt at a steampunk pouch, made of brass, nickle, and leather. The locking clasp is the only thing I didn't make, I bought it at Tandy Leather, a leather supply store.
As far as materials, here is what I used:
22 gauge brass sheet
20 gauge nickel sheet
A hide from Tandy leather
A leather dye
A turn-lock bag clasp from Tandy leather (http://www.tandyleatherfactory.com/en-usd/home/department/hardware/bag-clasps-closures/1307-504.aspx)
Brass leather rivets from Tandy, or your preferred leather or craft store.
Waxed leather thread
For tools, I used:
An adjustable jewelers saw and blades, for cutting out the details in the nickel
A Brake Sheet Metal Bending Finger Mount
A metal jump shear to cut the bigger pieces out