Check out Steve Lippia. Some people may say he is a Frankie impersonator but he sounds just like a younger Frank like 1940s/1950s.
http://www.stevelippia.com/music-video/album/steve-lippia
Lippia sounds great on Guess I will Hang My Tears Out to Dry and Night & Day.
Sounds like Frankie in 1940s/1950s.
His voice is very similar, but without Sinatra’s superb phrasing and precision.