Thanks, Frank, for your interest in GNATS and a flexible web interface.
Gnatsweb is probably the most flexible, as you noted, but is also
relatively monolithic. It was created before MVC was really applied to
web interfaces. Ynvge has pulled it forward and maintained it
separately from GNATS itself for some time, though like GNATS,
development has stalled. I'm certain he would enjoy any help you could
An optional login could certainly be coded up as a default value for
user and password. e.g. If user and password aren't provided, use the
default "guest" account. Should be a quick patch.
Customizing the page layout would certainly be easier with a template
framework. Mason would work, as would any number of Perl templating
engines. Going this route would ultimately mean a rewrite, though.
I'm under the impression that any flexible processing of unformatted
fields, like Audit-Trail is always going to be a custom hack. You can
provide some sort of helper with query format.
There are a couple projects that might help that are linked on the GNATS
gnatsperl, a collection of perl modules proving an interface to the
GNATS daemon written by Mike Hoolehan.