Comcast has a very understandable reason for deploying IPv6 to customers - it will be migrating to IPv6 as a company, and it does *not* want to maintain a dual-stack environment. First off, there's the reason why Comcast is moving to IPv6 companywide - IPv4 exhaustion within Comcast's own network. Comcast cannot stave that off, as too many devices that it deploys need IP addresses. As Comcast's customer base grows, it wil run into an IP address wall; not even NAT can prevent that. Second, the operating systems that customers run are, by and large, IPv6-aware now (Windows XP and later/OS X/Linux/the odd BSD and UNIX box), so the customers aren't really the problem. The biggest issue (at the customer end) is that we are used to having to use NAT to work around the IPv4 shortfall, and there will still be IPv4 in use elsewhere. (I'm not talking out of my hat; I'm a Comcast customer that uses an AYIYA tunnel from SixxS, and while there are IPv6-native sites that I can use, the vast majority of the sites that I use on a daily basis know nothing about IPv6, which presents a rather nasty problem going forward.) Therefore, Comcast will have to deal with IPv4 connectivity, and what better way to deal with it than at the edge, where their pure IPv6 network connects to the IPv4 space. (It's not even a new method; this is, in fact, used today, where pure IPv6 networks connect to the greater IPv4 Internet.) The bigger issue is indeed non-upgradable customer-premises-equipment (consoles in particular; remember, the computers are largely IPv6-aware); however, this is largely out of Comcast's hands (and out of the customer's hands as well); the console manufacturers (Microsoft/Sony/Nintendo) will have to solve it. (I have reason to believe that all three are at least passingly aware of the issue, as all three do business in Asia, which is much further along the IPv6 deployment path than even Comcast, let alone North America.)

Comcast is running several IPv6 trials this year. They are trialing 6RD, DS-Lite and native dual stack for residential customers and native dual stack for business customers. As a business customer I signed up for the trial a few months ago and will report if I'm selected for it (their site says it's scheduled for Q3). More info is available at comcast6.net.

They have Dual Stack, as addressed on http://blog.comcast.com/2011/01/comcast-activates-first-users-with-ipv6-native-dual-stack-over-docsis.html

You (and the press too) are way over-interpreting this. This is not a "pitch", it is simply an Internet draft to document and discuss the concept. First of all, the author of the draft has disclaimed that the proposal is even considered for deployment by Comcast. Technically the solution seems very interesting, not really new actually, for the late stages of IPv4 exhaustion to provide IPv6 customers with access to IPv4 resources. And at a late stage in the IPv4 Internet, it shouldn't really be very important where the NAT is located or how much less end-to-end connectivity one has, which no one behind NAT has anyways.

There is already a presentation[1] linked in the ARIN IPv6 Wiki[2] for a while. [1] http://www.6journal.org/archive/00000265/01/alain-durand.pdf [2] http://www.getipv6.info/index.php/IPv6_Presentations_and_Documents