Ken,
It was clever of you to insert your certificate chain in your message
to emphasize how much the naive reader has to wade through!
The headers are at the front because "all mail headers are the front."
That's the standard refrain whenever this issue is raised. I don't
think there';s any hope of changing this within the framework of the
current PEM spec. However, the situation is a bit different in the
integration of PEM and MIME. There are two proposals for how to
integrate PEM and MIME. One simply encapsulates MIME in PEM and PEM
in MIME, and it would not change the placement of PEM headers. The
other rebuilds PEM using MIME's structuring mechanisms. We have a
prototype implementation of this now working at TIS. One aspect of
the design is the headers follow the body. Look forward to seeing an
example in the very near future..
Steve