First of all, I know that this question covers a similar ground as Would it be possible for Stack Overflow to be accessible over IPv6? but the topic is one year old and pertaining to the last year's World IPv6 Day.
Today is June 6, 2012, the World IPv6 Launch Day, so I ask whether SE has made any plans to enable IPv6 on their servers in this year. Many large content providers such as Google, Facebook and perhaps most importantly Akamai have already made the switch so it is possible to access a somewhat large portion of Internet via IPv6 only.
Since IPv4 depletion is becoming more and more a severe issue we can expect that ISPs that won't be able to get new IPv4 allocations will start connecting their clients to IPv6-only connections or resort to CGNs which bring about many other problems such as identification of clients behind those CGNs and performance issues.
I think many users will appreciate IPv6 connectivity to SE and I think it is not a large problem from a technical viewpoint. A reverse IPv6 proxy will probably do just fine for the time being (similar to what Amazon AWS currently uses to provide IPv6 connectivity to their clients while they are upgrading the platform to the full-fledged IPv6 connectivity)