I'd also like to know that, especially as there are lots and lots of hosters out there who don't grasp IPv6 and are already breaking it before it has really tak

I'd also like to know that, especially as there are lots and lots of hosters out there who don't grasp IPv6 and are already breaking it before it has really taken off by creating pointless bureaucratic overhead and thus incentive to create bad network setups that will hurt us all. As for the cost for the hosting company: No, one major reason for IPv6 is that it has a huge address space with 128 instead of v4's 32 bit addresses, so they are a lot cheaper - as it should be, there is no point in artifically making addresses scarce. RIPE members, for example, are billed for an IPv6 /32 (about 4 billion /64 subnets) like for an IPv4 /21 (2048 addresses). In short: You should generally avoid any hosting company that allocates anything smaller than a /56, they probably haven't understood the internet.