Some days ago, i stumbled across Centreon (previously Oreon), a very nice web frontend for displaying nagios monitoring data, but also – even more important – it supports service and host configuration. Although the installation is poorly designed and not FHS compatible, the webapp is very nice and the generated nagios configuration looks very clean and sane.
I have created a centreon-1.4.1.ebuild with a (rather huge) patch for FHS compatibility in my overlay. I’d recommend it for every nagios user frustrated with editing tons of files for adding a host or service 😀