Oh yea, FWIW:

Netscape's proprietary options:
http://developer.netscape.com/docs/manuals/deploymt
/options.htm

Which supposedly allow file loads inline. But does
not work in OS/2 (I'll check windows).


Mailto url scheme:
http://www.faqs.org/rfcs/rfc2368.html

" The special hname "body" indicates that the
associated hvalue is the
body of the message. The "body" hname should
contain the content for
the first text/plain body part of the message.
The mailto URL is
primarily intended for generation of short text
messages that are
actually the content of automatic processing
(such as "subscribe"
messages for mailing lists), not general MIME
bodies."

Which basically means that the *decided* they
didn't want it to work the other way. If some
browser does allow file names there, it is
non-compliant. I read some of the lists on w3c.org
and it seems like it was just a matter of "We don't
do things that way" when the subject was brought
up.