I am trying to figure out a couple of things here.
1) Is the new 2257 requirements specific that you must have the ENTIRE work where the 2257 records are? Model IDs, cross indexing, and so on isn't enough? Could the same thing not be acheived with remote access to the client's server in case of an inspection? After all, unless the hosting is in your office, it would be remote anyway, right?
2) Does this storage have to be online? Obviously you won't be serving the content to anyone except the feds if they come inspecting. So the only online requirement would be to upload new documents / images / videos and nothing else. Once uploaded, it could be taken offline immediately, because it will never change. So the content could be written out to duplicated backups, example, and stored once in the offices and once in a secure, fireproof location.
I am trying to figure out why you want the content to be online.
Explanations, please!