I did a quick search for Christian western writers when I arrived home and I was surprised by how many there were. Elmer Kelton and Mr. Johnstone, just for examples, and I was wonderfully surprised to see some female writers in the historical western novel area blazing trails, such as Shanna Hatfield, Mary Connealy, and Jody Hedlund. Just to name a few.
If you're a fan of western fiction, don't lose heart. The genre is alive and well. You may have to search a bit to find clean novels that won't require a whitewashing of your mind afterward, but they are out there and gaining in popularity every day.