I ran across your post, and even though it has been ten years since you posted, I hope you still get this message.
I am the great granddaughter of Michael Schuller, and his second wife Mary Elizabeth Graff, of Mallard Iowa.Joseph Jacob Schuller is my grandfather and Virgil A Schuller is my father.
From various census records, I have found that Michael was born in Regensburg, Bavaria Germanyon May 8, 1834-35. He arrived in the US in 1867. And he died on August 12, 1902 in Mallard Iowa. Michael homesteaded in Palo Alto County Iowa in 1869. He was a carpenter and helped build the original St. Mary Catholic Church in Mallard. Unfortunately, I have not been able to find anything about his family in Germany.