I just created a Nagios / Icinga plugin for monitoring Red Hat Satellite 5.x repo sync states. This can be helpful to detect outdated repositories and taskomaticd issues.
The plugin checks file system timestamps and also queries the repo sync state using the Spacewalk API. Both checks are combined by default because not every channel offers sync state information using the API (e.g. Red Hat Enterprise Linux channels).
This is how the plugin looks like inside the Nagios / Icinga UI:
The toolkit requires Python 2.6.
You can see some examples and download the script on GitHub.
Maybe this helps someone here!