Welder needed to build cage (http://boston.craigslist.org/sob/lbg/2765576492.html)

I need an extremely sturdy cage built and welded. I need it to be lockable with a pad lock. I'm thinking about 3' wide, 4' long, and like 3.5' tall. I do not want it to rust. Having removable castor wheels would be a nice feature. I'm not in a rush, and want someone who is knowledgeable about metals and welding. I don't have any materials or equipment yet for this project.

I expect that this cage be built by someone with discreetness. I don't much want the neighborhood knowing what I'm having built.