Actually, an application type for MIME would seem to be more than sufficient... Perry Brad Huntting says:
If you've followed the PEM working group in recent years, you may have come to the conclusion as I have that it is not going anywhere, and probably never will.
In an effort to make e-mail crypto more wide spread, I suggest we draw up an internet-draft on the PGP message format, and the algorithms used to send and receive messages.
At the moment I can think of nothing PEM can do that PGP cant. Granted there are problems scaling the web-of-trust model, but PGP is also capable of using a top down model (really just a subset of the web model).
One thing such a draft is sure to do is send a clear signal to the PEM group that they must either start swimming or sink.
brad