I've always loved
Penelope and would use it happily. In fact, when our second daughter was born she had long, bright red hair and looked spectacular. We'd decided on her name, but I said "Shouldn't we call her
Penelope instead, after your cousin?" because of the hair! I was instantly reminded that Cousin
Penny wasn't DH's favourite relative, by a long shot, so our original choice stood.
I like
Penny and
Nell as nns;
Nellie doesn't appeal and
Poppy is appalling.