SD Card RAID System

Well, why. There RAID on SD cards. For example, for those who collect mobile robotics.

MS robots & mechanical men

The Pocket Mini Computer

Well, remember that this is just P8X32A 8 cores, that does not compare like with Tilera). In general, it is more like an example.

Get 64GB CompactFlash--via 4 microSD cards

PhotoFast's CR-7200 CompactFlash card adapter is capable of holding four microSD cards and combining their storage space.

You can make software RAID's almost over whatever the hell you want, however it's really not going to be all that useful since RAID setups almost certainly cause more write operations, especially when rebuilding, so your SD cards will wear out a lot sooner.

In addition to that, cheap SD card readers aren't really designed for data throughput, so you will have to put quite some money into those two card readers in order to use your also not too cheap high speed SD cards.

I don't know what you are trying to achieve, you may be a lot better off with a small SSD instead of SD cards.