If I'm understanding you correctly (and my apologies if I'm not), this isn't really quite the same thing - it sounds like a remote, encrypted filesystem. Dropb

If I'm understanding you correctly (and my apologies if I'm not), this isn't really quite the same thing - it sounds like a remote, encrypted filesystem. Dropbox and lipsync are file-syncing mechanisms, not filesystems. So, if you're offline, you can continue to work - your changes will be pushed to the server next time you're online.