Heh. Nice idea. It uses the old NextStep AppKit classes (rather than OpenStep, which Cocoa descends from) so you'd have to reimplement them, possibly as wappers around the modern AppKit api. It might also depend on some older features of the objective-c runtime, which would need to be worked around.
Could be a nice 'just for fun' sort of project though...
Could be a nice 'just for fun' sort of project though...