Here is a vintage painted-steel Steber barn or gas station wall-mounted light. It measures 12.5 inches across the shade. The rod is 14.5 inches long. It is meant to be hardwired and takes one bulb.

The paint on this is very rough. You'll probably want to rewire it. This will ship with the rod detached from the shade; you will need a flat-blade screwdriver to put it back together.