The first time I came across the name Penelope was in a Thunderbirds book. I naturally pronounced it (in my mind) to rhyme with antelope. This is better than the other way round, if only because it's hard to think of a joke about a coin running away to get married. I don't recall ever meeting a Penelope IRL and very rarely a Penny.
I have a very good friend who is a Penelope and she uses two different abbreviations, Pen & Penny. I also have a cousin Penny. I don't know if she is a Penelope or not. Furthermore, my older sister had a friend called Penny with whom she used to go horse riding.
So far as I am aware, all of these Pennies were minted in 1947, so not so rare as the 1933 ones.
My father used to have a small whimsy he would trot out from time to time. He maintained that his mother should have been called Penelope (she was actually Sarah) because my paternal grandfather's name was Inkerman (I can see no logic to this as he was born about 30 years after the battle of the same name) and then my grandparents would have been Pen & Ink.