If you are a horse person I promise you will be in paradise. Most shops, like the one pictured above, sell items from saddles to horse wormer, brushes, hoof picks, blankets, bits and a million other such things. Even if your not a horse person, I believe you will enjoy the experience. Go in and ask if they would be willing to make a custom leather belt, most will.
There are at least three harness shops in the Kalona, Iowa area alone. I make a point of going to all three even though I have my favorite. (I won't say which one) The shop east of Kalona a few miles and then south on a gravel road has mostly bio-harness. A nylon covered with a very durable synthetic coating. They also specialize in show harness.
A third harness shop specializes in nylon harness, and is located north of the leather harness shop, several miles on a gravel road (the road jogs west a little at one point.)
My two favorite harness makers are now deceased. One of them had a shop a few miles from my home and was one of the kindest men I have ever met. He was full of horse wisdom and told great stories, many of which appear in my novel, Under the Heavens.
I am saving his best story for my sequel, about an amazing pony.
My other favorite harness maker told me that he went to grade school with my wife's grandfather. He was a nylon harness man and also was a very kind, wise horseman, with great stories. Both of these men I used as examples for my Grandpa character in my novel, so if you read my book, know that there really are men like him out there in Amish communities.
Under the Heavens, on Amazon: http://www.amazon.com/Under-Heavens-Thomas-Nye/dp/1936746794/ref=sr_1_1?s=books&ie=UTF8&qid=1390142726&sr=1-1&keywords=under+the+heavens+thomas+nye