...
I believe the measurements code (pinger2.pl) will will work with both IPv4 and IPv6. Thus for monitoring sites pinger2.pl should be OK.
A simple place to start would be traceroute.ppl, since it does not require access any external modules, and is conceptually very simple. Some work has been done on this already, but only tested at NASA. It uses ping6 and traceroute6.
I suspect ping_data.pl will need some mods also.
...
An IPv6 host is ipv6.google.com(2001:4860:800f::68)
You can use http://www.subnetonline.com/pages/ipv6-network-tools/online-ipv6-ping.php to see if a host is reachable with IPv6.
...