Here's one idea. Here are some ideas and techniques to get you going. The edge of the vest back should fit just below the small of your back.
Western stores are also a good place to look.
Department stores may have them. Another interesting look would be to try you local thrift or Salvation Army store for a mans' wool vest. Choosing a faced pattern rather than a lined pattern, if possible, will save you lots of time. You can refer to my Patchwork Christmas Vest pattern for some ideas. There are many sources of applique designs that will save you from drawing.