Sarnia
I have Elizabeth as my middle name as my Grandmothers were Elizabeth and Eliza. In my family at least, middle names are usually family ones.
Yes, Elizabeth is a family name on my mother's side. It is a classic, timeless name that I have always liked and we gave it to our daughter as a middle name. One of my cousins and his wife decided to give their youngest daughter two middle names in honour of the two grandmothers. Sadly, the names were extremely dated, along the lines of Vera and Mildred. We felt very sorry for the poor child.