Ever seen a coat hanger that was made out of building hardware? How about a combination of cast iron piping and reclaimed wood- some of these ideas look really cool in my opinion.
Now how difficult it is to get your hands on that kind of material depends really on your location and resourcefulness. If you look on ebay, you will see that these do not come cheap though, so do some research and figure out the way to minimize the costs.
Once you get yourself some metal and got the idea for the design, visit a reclaimed wood depot or a construction site and their skip to salvage some nice wood.