A few years ago I released HostDB, my simple system for generating DNS domains. The LISA paper that announced it was called: HostDB: The Best Damn host2DNS/DHCP Script Ever Written.
I just released 1.002 which adds some new features that make it easier to generate MX records for domain names with no A records, and not generate NS records for DNS masters. Other bug fixes and improvements are included.
HostDB is released under the GPL, supported on the HostDB-fans mailing list, and supported by the community. This recent release includes patches contributed by Sebastian Heidl.
Is this based on the old generate.pl we used at Mentor? We still use that now at Virage, maybe I'll look at upgrading.