I was thinking of a way to let Zabbix get configuration data of a device.
I have a Zabbix agent for DD-WRT and Fritzboxes (Freetz) and I can write a function on it that collects the configuration data and send it to the Zabbix server.

I could then create a weekly item in the Zabbix server and pick up that data.
The configuration file could then be downloaded from the zabbix-server (a filename could be given for that in the item).