>>342
適当に辞書作ってsetattr,getattrをsetitem,getitemにマッピングすればOK

Class Foo():
_dic = {}
def __setitem__(self, key, val):
self._dic[key] = val
def __getitem__(self, key):
return self._dic[key]
__setattr__, __getattr__ = __setitem__, __getitem__

こうすれば
f = Foo()
f['x'] = 10
f.x
でアクセスできる