Yeah! Wow! That thing is so cool! I dreamed about a device like that years ago. I thought it would be ideal for installing surreptitiously at my school, in order to seed some torrents.
One of the users on their forum said that if you crack it open, there's still a bunch of empty space. Even though it would raise the cost a little bit, I'd like to see it add wifi, bluetooth, powerline networking (so it could act as a router between powerline and ethernet) and X10/zwave compatibility. Those things wouldn't add more than $20-50, and it would make the SheevaPlug a kind of hacker's Swiss army knife.