This displays the idea that a static number of keys is too clumsy for the task at hand. It makes more sense to set a rate of backup frequency based on key use. A scan of keys used compared to unused already occurs... Hell, it's a primary function of being able to tell the balance... Most of what you need is already there. The option to use a password or GPG key could be added on. Since mixing is unpredictable and continuous, it's only user-definable settings should be where to put the backup (default to the folder/directory already being used), and key frequency. It already makes backups at initialization. Just change that to the user-definable stats, add password/gpg passthrough, all done. Wouldn't want it to hit a cloud drive unencrypted... Wallet password and backup password/gpg should not be shared... I prefer to run my wallet unencrypted for recovery reasons. But I'd like my cloud backups to be crazy encrypted. Because duh. You might want something in the first use popup to talk about setting your backup frequency and location... Not merely disclaimer, but "do this or don't blame us."