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My take on this is that 'you're not amazon'. The world won't end if you're down for an hour or two. If the site was of any consequence, you wouldn't be hosting it on a dynamic IP for example (please - I don't mean to imply you're site's not fine - just put some perspective on it. This is my attitude with most people's sites, not just yours).
You're trying to limit downtime using a complex solution. There's far easier ways to do that. The first thing to do is find a solid host. Decent hosts these days basically never go down. Second is to make regular backups and archives. That will involve far less money and effort and are well known solutions, vs. the technical complex solution you're trying to employ.