Zope community, the largest producer of eggs !
If you check PyPI recent update any time, you can see at least one package update from Zope community. Zope 3 itself has more than 140 eggs . Zope 2 also started using eggs, I think Zope 2 itself is going be fully eggified soon after 2.11 release. It would be interesting to read Pradeep's post to BangPypers list along with this. He says: "The kind of functionality available in Zope and plone especially when it comes to fine grained authentication, content metadata, internationalisation support, are yet to be seen on other python framework. However, the choice is simpler now, because Zope is pushing for a ``Python Ecosystem'' rather than a single do-it-all framework . Once again they lead the way."