Larry,
Is it absolutely clear that use of the term "PostScript" in a MIME
message requires the annotation as well? I didn't read Ed Taft's note
quite that way. A somewhat softer reading is that the annotation is
required in the MIME specification document, and that the RFC must not
use the term PostScript to mean anything other than what Adobe means
by PostScript.
If this is the right interpretation, then it seems to me that
application/PostScript is precisely the right idea. The trademarked
term is intended to denote something that conforms to their
specification, and that's exactly the meaning to convey. Using
application/ps weakens the connection considerably and leaves open the
possibility that it may convey something like PostScript but not
quite.
Steve