WOW!! I can't believe that no one has taken a shot at this yet.
I'm certainly NO expert, but if there are no known FORD specialty restorers that can rebuild/restore your generator why not seek out a Chevy generator rebuilder/restorer.....I'll bet they'd do something very close to what it needs to be.
Go to www.chevytalk.com
I'll bet someone on one of those forums that I personally frequent due to us also having a '57 BelAir......
Also:(These guys DO NOT give me a good feeling, but here they are)http://www.youtube.com/watch?v=JWgvLPIQbUA