DNSBLs for IPv6

Solution 1:

Have you tried creating your own dnsbl on your DNS server and populating it with IPv6 addresses?
This puts the onus of maintaining the blacklist on you, but it also gives you the ability to custom-blacklist (or custom-whitelist) hosts & networks, which can be useful if you ever disagree with the major blacklists.

virbl (http://virbl.bit.nl/index.php#ipv6) has some notes on how they're dealing with IPv6 blacklisting which may also be of interest -- As far as I know they're still the only v6-enabled dnsbl provider.

Solution 2:

Due to the "unlimited" number of ipv6 addresses a dsnbl for ipv6 has only limited impact. We would need other technologies for the first line of spam prevention. There is a service provided by commtouch who checks only the hashes of the mail header, maybe it would make sense to put more effort in a "free" solution for things like that. Or maybe there is already one?