As a partial answer, using the -v flag with getMessage (or gm) shows some of the header information. It misses out routing information. However, the command zmmsgtrace gives that information.
So for example
Code:
zmmailbox
mbox> aa admin@myserver.com password
mbox> sm user@myserver.com
mbox> gaf
mbox> gf Inbox
mbox> s in:Inbox
mbox> gm -v 1274
mbox> quit
zmmsgtrace -s user@hotmail.com -r user@myserver.com
Having said that, I'm still trying to figure out how the message IDs work: when referencing a message by ID, it sometimes says it isn't there with one zmmailbox subcommand whilst appearing to show up with another.