Sonic.net's IPv6 tunnels are intended to be used only with static IP service, but they work just fine with dynamic IP service as long as one goes to the Member Tools to request a new tunnel every single time the IP address changes. Hurricane Electric offers IPv6 tunnels functionally identical to the ones Sonic.net offers, but a special protocol is used to update them directly with new IP addresses in the event of a change with dynamic IP service, analogous to the Member Tools page, except without the web. How feasible would it be to allow SOME automated way to request a new tunnel rather than require the use of the Member Tools page for it? The current state is analogous to Dynamic DNS service that requires the use of an actual web browser to update the address record, instead of the familiar update clients.
Because Fusion residential service includes a free static IP, we haven't had any impetus to address the issue.
In future, we plan to move to a native IPv6 6RD support in our CPE, and the point will become moot. =)