Jim's changes to zope.publisher (rolled out in version 3.5.0 of that package)
are probably relevant here:

 http://svn.zope.org/zope.publisher/trunk/CHANGES.txt?rev=84419&view=rev

For now I've disabled the tm and retry middleware in the grok  
package.  It would definitely be good if we could figure out how to  
create a new publication that didn't do these things.

- C

(Alas, grok uses its own publication derived from zope.app.publication's default
publication. So we'd also need a grok variant of that trimmed down publication.)

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.

The middleware pipeline in repoze.grok contains tm, retry, and vhm, but it's probably true that the 
publisher manages all of this stuff anyway.  What to do?