well that's pretty cool, if you pick one up let us know everything you can do with it. lol I wouldn't even know were to start with that.
heres where theyre for sale at my friend bought one so thats y i am. ΢ÈíXBOX360 XDK "XEDKÔÐÍ»ú" 158Ôª£¡ - ÌÔ±¦Íø XBOX360 XDK ¡¾¶«ÉýµçÍæ¡¿XBOX360 XDK Ô×°Êý¾ÝÏß Íâ½ÓÊý¾ÝÏß-ÌÔ±¦Íø XBOX360 XDK XEDK
Its likely to do with the sidecar that devkits have for debugging. Also just so you know the devkits on sale on that website have been intentionally broken before been disposed of by Microsoft, if you actually get one that works I wouldn't expect it to have the longest life expectancy in the world. From what i can tell from Chrome's translation at least the seller is honest about it:
lol would be funny if hackers got xboxs hardware key so we could turn ours into a debug just like the ps3 scene has lol