Quite frankly, it's dumb as hell to try to half-ass a redundancy solution when you evidently need as close to 100% uptime as you can get. You need to either spend the bucks on leased lines from tier-1 carriers and run BGP (contracting with someone for assistance if you don't have the know-how yet), or preferably you should colocate with a real datacenter and hope they don't go out of business. - jsw