A mithril sword? Seriously? My dreams have come true!
But I can do it without Elwing as well (just to show off
):
Elros -s> Earendil -s> Tuor -s> Rian -d> Belegund -s> Bregolas -s> Bregor -f> Barahir -f> Beren -f> Dior
Etc.
Anyway, we need an easy one now... Just take
Gil-Galad -> Dior Aranel.