One of my friends just had a baby & called her Jessica. I haven't heard alot of Jessicas or Ellas around here though.
I say if you love it then take the chance! We had DD's name chosen for 7 years before we had her & after having her heard that it was a popular name all of a sudden. We have only come across one other Brianna (in my mothers group funnily enough, so 5 weeks after she was born I thought they were going to be everywhere!) She is almost 4 now, we'll see when she goes off to school how popular it was but I honestly dont care.... I love the name & it suits her to a T!