Before we all go charging down the "let's steal from X.400" path, let's
have a reality check. The most cryptic gibberish I've ever seen in an
error report has come from mail that tried to get somewhere in an MHS network.
Rather than taking the X.400 stuff and adding on to it, why don't we
figure out what exactly works (not much), why it doesn't work (lotsa
reasons), and then how we should do it right.
My guess is that one can derive an acceptable minimal error report
format that bears little relationship to the features you find in X.400
and yet will still have an order of magnitude more real usefullness.