Cool. It’s still a little rich for my blood, but if you can figure out how to hot-swap the CF cards without losing data, this could be an awesome little gadget. It’s got a SATA interface, but you could probably rig it up to sit outside the computer so you can pop in new pairs of cards whenever you need to.
It’s difficult to say whether it’s practical at this point. The board costs $200, then you can buy a couple of these things for $70 each – that’s a 32GB solid-state SATA drive for about $350, or a 64GB one for $560 if you buy 32GB cards. That’s cheaper than the retail alternatives, and you have the benefit of being able to upgrade the capacity for the cost of the media.