As a network game programmer, this is sort of what I was telling everyone I knew a few years ago - that the real consumer push for IPv6 would be with video games. IPv4 address exhaustion will eventually force carrier-level NAT and make peered game connections and NAT traversal difficult in all cases and impossible in many.
Microsoft now needs to make IPv6 a 'brand' - something that consumers know to ask about and demand from their ISPs. A nice warning screen in the XBoxLive connection test telling gamers that because their ISP doesn't support IPv6 their gaming experience will be degraded should do the trick.
It's possible they could even update the Xbox 360 to do this as well (though without heavy branding to show that the update improves networking, users would likely be upset at a new 'you dont support ipv6' interstitial)
Microsoft now needs to make IPv6 a 'brand' - something that consumers know to ask about and demand from their ISPs. A nice warning screen in the XBoxLive connection test telling gamers that because their ISP doesn't support IPv6 their gaming experience will be degraded should do the trick.