Ooh, this thread is fun!
Well, think about this: Boromir and Faramir have at least as much Elvish ancestry as Aragorn - and their Elvish ancestress might still be alive, unlike Luthien. We don't know. If you remember, it says somewhere in the Appendices that an ancestor of Imrahil, Boromir and Faramir's uncle( brother to their Mum), married one of Nimrodel's ladies-in-waiting, who wandered into his kingdom, married, had a baby and, flighty being that she was, abandoned husband and baby and wandered off again. So, what do you expect from someone who hung around with Nimrodel?
(Probably because it would be extremely embarrassing for poor Imrahil to have to introduce his distant ancestress to all and sundry or to have to listen to her advice...) Of course, we don't get the lady's genealogy, so if she had any other descendants or if any of her ancestors were related to Aragorn's ancestors, we don't know. Well, I don't, not having yet read the complete HISTORY OF MIDDLE-EARTH.