Spotted this and picked one up at Poundland @ Merry Hill today.
Great looking and feeling play case for the DSI but should also fit the DS and 3DS.
Currently £8 on tesco website.
"With the Joystick Junkies pixel cherry Nintendo DSi play case, you can protect and store your Nintendo DSi games console. This funky play case from Joystick Junkies has a digital art inspired cherry print design on a black and white background. The case allows you to play your games console with it still inside the case. This case gives you full access to the functions and buttons of your Nintendo DSi."