You can, and this will work for a while. When it stops working (which is not at all predictable) you're going to need a fairly sizable IPv6 Internet so that you can continue to connect new customers up, and unfortunately, that means we need to start getting folks moving ahead of time since we don't exactly know how long your workarounds will last. I'd like to know when Google is going to go IPv6. Vint Cerf's answer was (essentially) "I'm pushing for it."
The problem is twofold. First, if Google isn't going to index IPv6 content, no one cares if their content isn't available that way. Second, when other people try to explain IPv6 to management they often hear "Is Google using IPv6?" Heck, Google could offer incentives for IPv6 deployment and suddenly people would clamor for it- say side by side results. Most appropriate IPv4 on the left, most appropriate IPv6 on the right. (Even just an IPv6 icon that people could click on to learn about IPv6 would help). -Don