[VoiceOps] 911 backup solution

I'm looking for a viable backup solution for 911 calls. Here is a hypothetical question: If you had an E911 provider already but wanted to ensure that every 911 call is answered, even if that e911 provider is unreachable or unable to take the call, how would you accomplish this? Does anyone know of a provider that will accept 911 calls for any ANI, even if there's a hefty per-call cost? -- Victor Breen, VoIP Systems Administrator Impulse Advanced Communications (805) 456-5800