DNS error records

[homo]

Hi,
I would like to know if it's possible to build a opendns.com like dns application.
I mean, that i want the dns server (BIND, PowerDNS whatever) to generate a record to point to a website in case an error occurred. Opendns.com provide a info page in case of an error providing which nameservers failed etc.

[homo]

Is it possible to use a firewall dns rule to forward queries that can't be resolved like this tutorial: http://www.howtoforge.org/using-dns-name-object-in-firewall-builder

i want to provide a dns service that will infrom users if a domain/host isn't valid