Thanks, pakon looks to be targetting exactly what I have in mind, though it seems a little young (no web interface) it seems to be aiming to eclipse majordomo (as evidenced by the FAQ What is the difference between “Majordomo and PaKon?”.
I will take a look at pakon and play with it and maybe its source if I can find it ;-). Personally I’d love to see tool (and maybe just maybe, though not likely, build it myself if I have to), that does a reverseDNS as I described above (checks the history of DNS requests - name/IP pairs that knot or dnsmasq resolved first (to get the most relevant users perspective on things) and then dig as a fallback.