I understand about finding "the one." Mexican art is so varied, and each one of us has an idea in our head of the exact one item we want. A few years ago I wanted to purchase a Mazatlán Sun. They come in many designs, some happy, some somber, some scary. There are "folk art" suns, and more fancy looking ones. Some have countryside scenes within them. They are also different shapes and colors. I had a fairly good idea of what I wanted. I went into a shop which had nothing but suns, over five hundred of them. Guess what? It didn't have mine. I looked in every shop I went into for six days before I found the one I wanted, and I know the town good enough to know where to look.
So good luck with your search, and don't give up until you find the right one.