So, it's been a year and a half since I last did anything with IPv6. Lots of life has happened since then but technology marches on. After upgrading my gateway/DNS/firewall/router to Scientific Linux 6.3, I have been deluged with DNS errors because IPv6 addresses aren't resolvable on my system. I guess that's an indication that I really should pick back up on getting IPv6 working.
My plan is to do a phased roll-out of IPv6 with the first phase being to just get it working alongside my existing IPv4 network. That means setting up DHCP6 and DNS for internal systems and then getting local services like amanda, NTP and NFS to work with either protocol. Once I get to that point, I'll see if I can get an IPv6 tunnel working again but this time as a gateway.
Update 31 May 2013: Here's a hint at how things are going...
Lots of progress so lots of updates to come but it's basically working. Still can't get reverse DNS to work for DHCP assigned addresses and dhcp6d and dhcpd seem to not be able to coordinate updates to files like /etc/resolv.conf but those are details for future postings. The body of this post (from the summary break, on) has not yet been updated.