I too have been looking for a case for my DX but I want something nice, those tend to be expensive, so I'm holding off for now... In the meantime...I bought a portable dvd player for my wife and a sleeve that she never used, I appropriated the sleeve and it fits my DX perfectly and much cheaper than the "e-reader" branded.
http://www.amazon.com/Case-Logic-Neo...593374&sr=1-17 I got a black one.