I *believe* this should be handled via the config push and the ifconfig driver at https://github.com/dreamhost/akanda-appliance/blob/master/akanda/router/drivers/ifconfig.py.

Here's an example where I did a `neutron router-interface-delete` on an existing router, watched the rug do a config push, and then verified that the v6 address no longer existed:

http://screens.objects.dreamhost.com/04-08-2014-16-20-37.png

...notice in this example how, after the router-interface-delete, `inet6 fdd6:a1fa:cfa8:962e::1 prefixlen 64` disappears from the appliance.