My dd is called Eloise. At the time we chose it, we weren't sure if it would be seen as a bit unusual so the option to shorten it to Ellie was there for dd in case she didn't like the full version when she was older.
I didn't think it would be so rare as to never hear of another one but she's 9 now and I've only ever heard of 2 others, and one on holiday.
Is it common or rare where you are?