This idea came to me some time ago as something that would be interesting, and since getting involved with Raspberry Pi, I thought it would be a good fit as an add on device. However, I lack the hardware skills to actually make something like this happen, so my idea has floundered. The idea is to use SD cards in a stack to construct a RAID device for small systems. This could provide the Raspberry Pi with a secure storage solution that would be scalable, and not use as much power as a USB hard drive. I have seen several cloud solutions using RPi, but they always fall way short for secure storage, and SD cards fit the bill for the I in RAID.