I know a little girl named Arin. Rather than using it as a alternate spelling of Erin, her parents considered it a female variant of Aaron (the name of a grandfather that had passed away). If you are wondering what the difference is, I live in an area where Erin and Aaron are pronounced differently - Erin is ERR-in and Aaron is like AIR-in. The Arin I know pronounces her name AIR-in. Although a lot of people ask "You mean Erin?" when they first hear her name, I think it really suits her.