Databeestje, I do have a question if your code handles a 6RD configuration as comcast is supposedly set up to handle that across their entire network already. if not, I dont think its worth it as Comcast is dropping it after June 30, 2011 anyway in favor of dual stack.

One of the largest cable internet ISPs in the Netherlands called Ziggo still has no plans for IPv6. This is pretty much the trend for internet providers it seems.

Some detective work has found that their ASN in the routing table does not even have a IPv6 prefix. That's just plain dumb. There are places you can start.

You are right when you say that Ziggo is just plain dumb when it comes to IPv6.
I'm in the same boat and when I called Ziggo about this (and a few other things) a month or so back, they were about as cynical as you can imagine.
In short they think it's not going to be a problem for them as they have enough IPv4 addresses to last them a few more years.
Other ISP's in the Netherlands aren't doing much better, though XS4ALL is the notable exception.

I believe I read somewhere (tweakers.net?) that most of the new fiber providers are running dual stack by default, so shiny new consumer/SMB ISP's such as Zeelandnet, Surfnet, Solcom, Tweak and Lijbrandt may be our best bet for the future when it comes to speed and IPv6 in the Netherlands.
If I'm wrong and they aren't running dual stack, it is far more likely that 'we' as users can persuade them to implement it because they are still small as a company.
That, and of course the fact that IANA is set to run out of IPv4 addresses today or tomorrow will help as the price of IPv4 addresses will probably skyrocket.

Some detective work has found that their ASN in the routing table does not even have a IPv6 prefix. That's just plain dumb. There are places you can start.

They have approx. 1 million or more subscribers in the Netherlands. This is the same ISP I have at home.

I've been using a Hurricane Electric tunnel at home as a alternative.