Yup, zope.publisher knows how to retry requests and how to do vhm, and the
default publication in zope.app.publication does the transaction management.

I think it would rock if we could "explode" zope.publisher +
zope.app.publication into WSGI middlewares as well. In fact, I think most of the
stuff is already available in repoze, we'd just need to write a pulbication that
simply doesn't do any of the stuff we do in middlewares.