incedently, I started toying with makeing a new POF editor recently myself, well actualy its more of a generic binary file definition and editing program (eXtendable Editor Naritive Utility), but POFs were the files I had in mind. it uses an XML like text file to define a simple file structure, currently I intend to get a basic editing capacity, then add in scripting, then add in graphics as a plugin. the way I'm doing it is IMO neat due to the fact that it uses no predefined complex structures for handleing data or manageing files (it uses a dynamicly genorated tree, each node handles both data managment and editing functionality of the data it is explisitly responsable for).
the aproch I'm takeing is not to make the best POF editor, but the most flexable and adaptable, if I do my job right changes to the basic POF file will be a trivial matter of editing some XML(like text, it's not actualy XML).