> 2. Anyone else who writes or have written anything like this? I will
>    contact the people behind Mailcrypt ASAP.

Below you find a message I sent to them a few months ago which summarizes
the changes required for proper detached signature handling.  I'm afraid,
but I didn't get a reply.

I'm working on a clean interface to GnuPG which is written from scratch,
but I got carried away once more, this time by some Emacs bugs. :-/

Currently, it's complicated to get meaningful and machine-readable
status codes for signatures from GnuPG or even PGP.  A coworker of mine
is working on a proposal for machine-readable status codes for OpenPGP
signatures with standardized semantics.  Discussions has just begun,
but we plan to provide a sample implementation based on GnuPG.