Custom config at bootup

[plaap]

I was wondering if it would be possible to let pfsense download a config file from a predefined location, load it and then reboot with the new settings. This doesn't have to be the complete configuration file but only some typical parameters a would use.
The plan is to rent pfsense devices as wireless CPE's and depending on what type of service the customer wants the devices get configured. I'm mainly thinking about traffic shaper global limit, 1:1 nat of external ip's, disabling opt ports, etc…
I could probably fit it somewhere in the rc.bootup and then reload the settings but there's probably a better way to do this so it can be reused. Maybe a package?

I would appreciate any pointers.