Now 1.6 is out (thanks!), can we figure out how to get these patches (or
any other such fixes for the same issues) reviewed and into Roundup
trunk, so that future Python 3 improvements can take place incrementally
in trunk starting from a baseline where many things already work, and so
that future unrelated code changes are less likely to accidentally
introduce more incompatibilities by copying code using old idioms?

A reminder: the version of patch 1 attached directly to this issue is a
rebased one that supersedes the original one in the attached tarball. 
Patch 38 was already applied for 1.6.  These patches don't do anything
about the mailgw.py use of mimetools; if desired I could provide a
version of my mailgw.py hack that avoids breaking things with Python 2
while still not actually making it work with Python 3, but really what's
needed for mailgw.py's use of mimetools is review / commit of John
Kristensen's patches to move it to using the email package.