Hello I'm Daniel and I am an the man who stay behind a HODLER security model.
Okay, to start, care to elaborate on "the computer being the weakest link?" As a Trezor owner, I'm genuinely curious on how my virus infected computer could steal my coins.
Hardwarewallets that require computer connection are subjected to attacks that can take over clipboard of the infected computer. Our wallet in completely independent. Clipboard hijack attacks are happening more often than breaking of the double encrypted connections and archives. For readers not familar with this technique:
http://whatis.techtarget.com/definition/clipboard-hijack-attackWhat's the point of a cloud backup, if the user has to remember a password anyway? Forget about the cloud storage, and use a 24 word recovery seed instead.
Cloud is dedicated for storing encrypted blobs of IMPORTED wallets. These wallets can not be generated once again from seed while recovering backup, so we storing it safetly in cold storage. Blobs are generated in that way:
generatedHashAsKey = sha256(seed).repeat(100000)
blob=aes256CBC_encrypt(generatedHashAsKey,importedPrivateKey)
And this blob is sent to cloud with point-to-point encryption.
With this storage, when you can recover imported wallets when eg. you lost your device.