For those of you, who like me, have too much time on their hands, and are following the mystery of the 60 amp GFI w/out neutral terminal, I've done what research I can and have concluded that most applications for a breaker of this size don't need the 120V leg that a neutral conductor provides in a 240V circuit.
I'm not sure how many spas out there outside of some of the Sundance spas have an option for a 60 amp setup and also requiring the use of a 4 wire circuit (2 hots, neutral, and ground).
I have no idea how true this is, it's just what my sources speculated.
