Back in my college years I applied for a job at a company that provided computing power for a stock trading company. Understandably here, time was money, and so part of their disaster recovery plan was a complete duplicate of their internal setup that was, and I quote, 'kept in the back of a lorry round the corner'.

The intention was that in the event of some sort of failure, they could bring the hardware out of storage and get the system back up and running within a couple of hours.

Sun now provides something similar, but perhaps more off-the-shelf than a custom built setup in a lorry, in the form of Project Blackbox. The concept is interesting -- take a standard-sized shipping container, stack it full of the equipment you want and then provide a single access point on the outside with power, networking and cooling connections to provide a ready to run datacenter.