Frankly, I like this idea and wish Apple would do it with iCloud. So does Ron.
Another way that caught my eye comes from BackBlaze. Think of this backup system as iCloud without all the glitter… BackBlaze is just hard-nosed cloud backup. You decide which files go into the BB cloud, then set it and mostly forget it. The Mac app works in the background to copy files to the cloud; the first copy takes longer, but subsequent backups only copy files which have changed since the previous backup.
iCloud on the Mac does something similar with Documents and Desktop files, but BackBlaze is less expensive for unlimited online storage.