I have no idea about the state of IPv6 in Perl, but I attended the German Perl Workshop a few weeks ago and there was a speaker, Steffen Ullrich, who was talking about it. He works at a company making network appliances (www.genua.de), and they recently ported a firewall appliance to IPv6.

He said that Perl support isn't quite complete, but it's doable. He wrote the Net-INET6Glue CPAN module: "Make common modules IPv6 ready by hotpatching".

So look into that, and maybe contact Steffen for questions.