Michael,
I was unaware the ISPs were using a "service." However, wikipedia has a Barefruit article and a list of competitors in the space...
http://en.wikipedia.org/wiki/Barefruit
Competitors (from wikipedia):
Some of Barefruit's competitors in the DNS error space include Nomimun (the founders of BIND), Paxfire, Golog, Simplicita (recently acquired by Sandvine) and OpenDNS. There are currently no competitors monetising http errors.