6to4 for iPhone?

It occurs to me that adding IPv6 support to the iPhone, or indeed any mobile device like it, would be relatively easy. Since they have a routable IPv4 address, they could easily do 6to4. When on via WiFi, they could use router and prefix solicitation when available, and when not, then it simply wouldn't be available, but there's really no reason why 6to4 couldn't be used on the WAN interface. It isn't as if it adds any overhead when it isn't being used. The benefit would be the ability to surf IPv6 only sites transparently, plus moves us all closer to IPv6 adoption. It also would pave the way for AT&T to upgrade the network to native IPv6 with IPv4 support via NATPT. That too could be accomplished transparently, if they were careful.