The William Francis Dunston [with an 'o'] who arrived at Ellis Island in 1910 listed his profession as 'butler.' In the 1920 census, this man is in North Hempstead, Nassau County, NY with his wife Ellen. His age is recorded as 43; his wife 44. He was working as a butler in a private home. Ellen was a dressmaker working at home and she was listed as the head of household. She was also an immigrant from England, arrived in 1908. They were both naturalized.
If you think this is the right man, let me know. I crossed him off before because of the wife's name and because the other guy was married to a woman named Brownie, which struck me as an unusual name.