I looked at that quite a bit when I built the car. It would have to be a rear steer rack, and there just isn't enough room to put one in (oil pan interference) It would make life a lot easier if I could.
(I know squat about '57's, so keep that in mind)
Based on what you said, it looks like no matter which route you go for PS, you have to modify/change things up.
What kind of oil pan mods are needed for the rack to work?
Beautiful car. I'd love to have something vintage one day.