Frank Ess and Rose Ann Miller were one of my sets of great-grandparents. My mother Mayme Ess Rolf, knows a great deal about the family history and my sister-in-law, Leeann Elaine Rolf has extensively researched the family.
They emigrated to Montana around the 1880s. Great-Grandma Ess lived until the mid-1940s and my mother knew her grandmother personally. They had several children, Ida, Earlin, Levi, Joe (my grandfather) and Hazel.
Feel free to contact me although I see it has been several years since you posted this, you may have already received information about the family.
Christine Stevens