I have repeated the 6to4/6RD interop experiment, this time using a DD-WRT router instead of a Windows 7 host. (The specific router was a Linksys WRT160n running DD-WRT v24-sp2 (01/02/10) std-nokaid-small, build 13575.) The outcome was positive for the DD-WRT router: it performed as theory would suggest: only minor configuration changes were necessary to turn the DD-WRT router into a working 6RD customer equipment host.
With two different IPv6 6to4 tunnel implementations we have had apparent success configuring the routers with only minor changes to enable deployment in a 6RD domain. It’s nice to actually see the expected behavior.