I was thinking a real slave zone. Some of our customers keep the DNS at their domain registrant or we provide the DNS service for them. If we take down the main DNS server for maintance they would not be able to resolve to their server.
The solution would be to have slaves of the master zone file on their servers. It would be really great it we could have a option in at least the Admin area to add the domain and ip of the master record!
I would really apprecaite if in some future release if that was a option.