Just sitting and pondering easier ways of administering Nagios and I thought of something. In the cfg files, would it be possible to use some PHP code to connect to a database, print out all of the entries in a Nagios readable format, then have Nagios read those entries? Or if not PHP, could it be done with Perl/C?
you can always try to parse the cfg files 
I think there already a re a couple of “managemnt” tools for nagios… not sure how they work haven’t looked at them for a couple of years.
Keep in mind there might be even something usefulk for Icinga, which right now accepts the nagios cfg files as they are…