http://dns.measurement-factory.com/tools/dnstop/ 20050405 in portage. dnstop-20060517.tar.gz available.
dnstop-20070105 is available, revbump needed. Only copyright change is needed. I put it in my overlay "pkalin", anybody can use it with layman. See http://rsync.tar.bz/README.txt
latest version is now 20070510
dnstop-20070510 in cvs.