The expensive part about data centers isn't the square footage, it's the HVAC/power/bandwidth/servers. So you have the space, that means you still need to reserve twice the bandwidth, power, cooling and hardware. x2 cost. Actually somewhat more because you need to account for all the bandwidth and time to keep everything synced up.
at what rackspace can charge, new hardware is nothing. the problem is that if I rent you a server, it's going to be pretty difficult for me to replicate that server to another location without a lot of cooperation from you. the more I screw with your server, well, the more likely I am to break it, too.
