Heartland, a company that suffered a massive data hemorrhage, is now looking to split up their data between 50 or more servers. The data won't be encrypted and they won't use any other translucent techniques, but the damage from a break in to a single machine will be limited to 1/50th of the data. Chris Walters at Consumerist has a long interview with Evan Schuman who lays out the limitations forced by Visa and Mastercard.
The problem is that a weakness in the OS of one of the 50+ machines is likely to be repeated in all of the machines. IT managers like to keep things standard. That means an attack could be automated to slurp data from all 50. Oh well. It's a start.