We basically have the logging in place, it is called AGENTATTEMPT and was before Asterisk standardized on RINGNOANSWER.
After giving this a bit of consideration, this is not very easy to do, because
a macro can only be called when an agent answers, and so this is not
generalizable. We can of course make it work for LOCAL channels, or we could
write a very simple, trivial patch to the app_queue module, but this would make
deployment of a QM system a bit more complex for "canned" systems, and this is
not what we would like to do.
On the other side, people are interested in ringing to know whether the call is
being mis-routed or agents are not answering thus causing delays. We already
have this information, so this is something that we are going to implement as
issue #1306.
If a call, while unanswered, has failed attempts, I would display the name of
the agent that was called without success and maybe the duration or the number
of failed attempts. These would be displayed in red. This way you get kind-of
the same information you have when ringing.