zc.dict (pypi): BTree-based persistent dict-like objects (regular dict and ordered) that can be used as base classes.  This is a bit of a heavyweight solution, as every zc.dict.Dict (and zc.dict.OrderedDict) is at least 3 persistent objects.  Keep this in mind if you intend to create lots and lots of these.  To build, run ``python bootstrap/bootstrap.py`` and then ``bin/buildout`` from this directory.  A clean, non-system Python is strongly recommended.
Keywords: zope|zope3