As mentioned in my previous entry on 'NFSMAPID_DOMAIN', there was going to be an internet draft for the DNS TXT RR solution to finding a proper NFSv4 domain, and Rick has now submitted it: http://www.ietf.org/internet-drafts/draft-mesta-nfsv4-domain-01.txt

Section "2.3 IETF DNS Community Considerations" is interesting as it hints more work is needed in the future.