The retracting mechanism for the steel roof is incredibly complex, few people really know how to work on the mechanism, and parts for it are in very short supply. Additionally, no body parts aft of the doors are identical to any other '57 Ford, i.e.–even if they look similar they are unique and in VERY short supply.
Thus, few restorers have the skills and/or parts to do this job properly. Don’t “cheap out” on this one, as these cars are rare and are potentially among the most valuable cars of that era. A restoration that is not done properly will degrade the value of this car. Do it correctly, even if it means spending a few thousand $$ more money. And, remember that when you begin a restoration like this, the unanticipated expenses will very considerable, thus adding to the total bill no matter who does the restoration.