In case you haven't seen this one yet:
http://tools.ietf.org/html/draft-gont-opsec-ipv6-implications-on-ipv4-nets-01
It seems Ipv6 can have an impact, even if you think you have IPv4 only.
http://tools.ietf.org/html/draft-gont-opsec-ipv6-implications-on-ipv4-nets-01
It seems Ipv6 can have an impact, even if you think you have IPv4 only.