It seems to me that the world of EBCDIC-only mail isn't really part
of the Internet proper (since RFC822 requires US ASCII). The thing to
do would maybe be to not explicitly include a Content-type
text/us-ebcdic and instead leave that to agreement amongst the "local
enclave" of EBCDIC users.
I think that if anything is said, it should be made explicit that
EBCDIC hosts talking to US-ASCII hosts have to talk US-ASCII across
the SMTP link. In other words, the burden of ASCII-EBCDIC
transformation should always be with the EBCDIC gateway host.
It would be a bad thing if messages encoded in EBCDIC suddenly
showed up on the rest of the net...
Ran
randall(_at_)Virginia(_dot_)EDU