Nice, is there a command similar to this for the port forward table?
Port forwards are saved in vts_rulelist. QoS rules are in qos_rulelist.
You can get the whole list of settings by running:
nvram show
To save it to a file, assuming you have a USB disk mounted as sda1:
nvram show > /mnt/sda1/settings.txt
You can selectively restore many settings by using the same method (as long the format hasn't changed between firmware versions, of course).