I've done some nebulous preverbalized stuff with NSData and similar classes such as alluded to in TextArchitecture.pdf from Apple.
I believe TextIO.pdf shows how to make a non document based application to deal with raw text rather than force use of NSAttributedString or rtfd sort of textstorage method return for NSTextview.
I had seen, in modula, a way to what is called "flatten" objects and save them. I don't know if there is a class or polymorphic method inherited from the big daddy, NSObject, that does this.
I think it would be nice if there were to start to clean up the model making part of MVC.