Well I finally brought the code up to spec to match the internet draft being written:
Draft-groth-dns-encryption - Toronto Asterisk Users Group
I produced a fastagi script that works in 1.4.x version of asterisk:
http://www.e164.org/enumlookup-0.0.4.fagi
The script doesn't currently verify or check cached certs or periodically check for revoked GPG keys, although this is all client side stuff and should be done if for no other reason than to have a complete working example.
The internet draft needs some spit and polish and it also needs some paragraphs on how the PGP web of trust can be used as a defacto 'Certificate Authority' using the masses to verify the servers of the world etc.