Passwordless multi-account SMTP

[Jacek Generowicz]

Hello,

I'm trying to use notmuch from Emacs. I have a number of SMTP accounts
through which I would need to send mail. Suggested solutions I have
found fall into 3 categories:

+ Gnus posting styles. (I'd rather stay clear of gnus, at present.)

+ Writing plaintext passwords in the MSMTP config files. (I'm rather
  relutctant to leave plaintext passwords lying around.)

+ Emacs' own SMTP library. (I don't understand how to get it to deal
  with many accounts in a non-gnus based way. It also seems to be
  undergoing an interface change in the transition from Emacs 23 to
  24, and it was already confusing enough without that complication.)

To further complicate matters, I'm looking for a solution which queues
any messages which are sent while the machine is offline. (It seems
that MSMTP and Emacs SMTP library do offer some help in those
respects.)

Hints gratefully received.

Thank you.