I just skimmed the PyCon 2005 presentations and papers, and it was interesting to see a few that present ideas that could also be implemented using simple generic functions. For example, Zope 3’s subscription adapters are something you could do using a custom result combiner. And another paper talks about method combination patterns. The cool thing about finding this out now, is that I can now use those other systems as a basis for comparison in my presentation, which may lead to more interesting discussions.