However, I think I'm missing something. Why do you need to use UTF as
an encoding? Why can't the sepc for iso 10646 as a character set simply
say that it the "raw" data is UTF-encoded 10646? If the only use for an
encoding is to encode a specific type, then it isn't a
content-transfer-encoding, it's simply the chosen representation format
for that specific type.
That is a possibility, but UTF is really more general than just an
encoding of 10646. It is the equivalent of quoted-printable
in the world of 8 bit transmision.