dynamic-host=cafe.dxld.at,::cafe,lan0
Firewalls tend to support DNS, use it :) pre-up ip token set ::cafe dev $IFACE
This way when you get a new GUA there's no need to "renumber" your network manually as everything will just happen automatically. When your router includes a new prefix in the router advertisement all hosts on the LAN generate new addresses for this prefix.
BTW: Contact info is in my profile if anyone wants the inside scoop. The project just isn't fully ready for public launch yet, but we're well into the cooking.