I'm writing a short novel mostly for my own enjoyment, but I want to know if the elf and prince forbidden love has been beaten to death and if it would actually get any attention if it were to be published
Stories about love between men or women and fairies are as old as the belief in the latter. There are countless folk tales, traditional ballads, and medieval chivalric romances that recount such relationships. And when you go to the Young Adult fantasy section of a large bookstore, you'll see that there are many books that tell such a story as well.
So, yes, the story of a love between a human and an elf has been told and retold quite often, but the strong ongoing fascination with the topic seems to indicate that it hasn't yet been "beaten to death" nor will it every be.
The same goes for forbidden love. It is a topic as old as love and it is still one of the most popular tropes today. When you browse a relationship advice forum on the internet you'll quickly realize how it is an everyday experience for quite a few people whose parents or friends disapprove of a love interest because he or she is the wrong ethnicity, comes from the wrong background, isn't professionally successful enough, isn't a vegan (or is a vegan) etc.
So, again, this is a trope that has been used often and yet is never going to lose it's fascination for us.
A character wanting something they can't have is great conflict – in fact, it might be THE conflict at the root of all good stories.
The set-up is a classic, but the story needs to go somewhere. It can't just be un-consummated puppy-love.
What your characters do about this conflict can be completely original. That's where the real story begins.