DNS is really just a huge peer-to-peer network with a few central nodes, so this shouldn't be too difficult. You can already use an alternate primary nameserve

DNS is really just a huge peer-to-peer network with a few central nodes, so this shouldn't be too difficult. You can already use an alternate primary nameserver, such as Google's 8.8.8.8. You'd just need your alternate nameserver to maintain a different cache than all of the other servers.