Scheduling deferred sending of emails

[Claus Assmann]

Just some idea (untested):
Use a script as "sendmail" program for mutt which
- submits the mail but tells the MTA to only queue it,
- gets the info about the queued msg from the MTA when
  it accepts the mail,
- schedules a queue run for that item at the desired time.
and make sure the MTA does not run the msg any earlier.

For sendmail:
- use -odq
- the script needs to parse the output
  250 2.0.0 $QID Message accepted for delivery
  and get the "queue id" $QID.
- use at to schedule sendmail -qI$QId
- either do not run the queue at all or put your submitted
  mails in a "queue group" which is not processed by default.

For details: see man sendmail and doc/op/op.*

Other idea: use quarantining (also see doc/op/op.* from
sendmail for details).