Well, not only former Be but former Finder developer here. The OSX Finder was certainly not a cute Finder-like skin, it was in fact huge amounts of the OS9 Finder source code including a complete copy of a modified Metrowerks PowerPlant C++ framework underneath it all. There was even elements of the old MacApp framework there. It was not a skin; it was a source code behemoth with massive amounts of legacy code.