My ISP has apparently made no progress whatsoever with IPv6, but I've got an IPv6 enabled VPS.
SSH makes it trivial to use that VPS as a SOCKS5 proxy. Just do:
ssh -D 8080 myvps.example.com
Then set your browser's SOCKS proxy to localhost:8080. In Firefox on
Linux, this is Edit > Preferences > Advanced > Network tab >
(Connection) Settings > Manual Proxy Configuration. Leave all fields
blank except for SOCKS Host and Port -- localhost and 8080,
respectively. Choose SOCKS5. Then browse to about:config and change
change network.proxy.socks_remote_dns to true. This tells Firefox to
ask the proxy to resolve names instead of trying to resolve them using
your ISP. Chrome worked for me without hassle.
Go to test-ipv6.com to test that it works. If your results from test-ipv6.com indicate that IPv6 name lookups are failing, make sure you've got that about:config setting mentioned above changed.