I wasn't really aware that sessioncrumbler was plone-only. My initial suspicion would be that it would include a template or so that's usable in plain zope. Perhaps search for 'session' in the zope.org product search one more time? ...
The most obvious feature is the Holiday Dip during the week of Christmas, although new visits didn't collapse over the vacation. However, if one looks closely (very closely, trust me on this) the "teeth" of new visitors line up ...
