slightly OT, 7bit clean mail headers, or converting into this form

Hello,

small question...

per rfc, email headers must be 7bit clean (everything else must be
encoded somehow)

postfix has an option to reject "non-clean" email (very efficient, and
way too efficient
considering the number of broken mail clients out there)

also, the cyrus-imap server i'm currently evaluation for my employer
also doesn't
like 8bit characters in the email headers (because of indexing, et all)
it (cyrus) has an option to allow 8bit chars (in fact it converts then
to an "X" before
putting the mail into the store), some subject are quite foobar'ed by this

knowing that
1) this replacement in cyrus is not quite "acceptable" for my employer
2) i cannot convince everybody out there to use "clean" mail clients
(not that i wouldn't like to...)
3) i also cannot reject email just for this reason (i've tried to
convince the management, but...oh well)

does anybody know of a good "header converter or sanitizer" script ?
it would be even better if it was easily interface-able as a postfix
content filter

i known that some people will say "you can't encode it right unless you
know which charset locale
was used in the first place", but this point is less important for us
(we suppose, being in europe,
that it will be the standard 8859-1 charset)


Thanks alot

PS : i know of at least one product (Sun's messaging server) which did
this header conversion
automatically (albeit with some funny results at times, because eudora
did half the encoding, but
still left some "should be encoded" chars in the headers, thus
triggering a second reencode of
the header, which then went out with a double encoding :
(encode(encode(header)))