SBS Disaster Recovery Plan

Good morning all! Happy new week!

One of our subsidiary sites runs a three-server setup based around SBS2003R2, there's also a NAS box that stores all the user data and a new 2008 server that's currently only running SIMS + some data storage. There's no user data stored on the SBS box apart from mailbox data.

I want to build a second SBS box so that in the event of the existing SBS box exploding I can simply plug in the "backup SBS box" and be back up and running in the minimum time. How can I best achieve this?

I do not want to clone from a backup of the existing SBS as I'm suspicious that it has some underlying issues and don't want these issues replicated; I want to build the new box from scratch and keep it in a cupboard, just in case.

Any advice, or pointers to existing threads and articles would be very welcome. Thanks.

Does the thundering silence mean that this is a bad / stupid idea?