The Sony Digital Paper has an official case and the model number is DPTA-RC1. Sony sells this case as a bundle with the DPT-RP1, but can also be purchased as an independant accessory for $59.99. It has a flexible design and is of high quality. It features a stylus holder, so you can still keep your stylus firmly attached, and a sticky back sheet for firm and easy attachment.
We have found that the sticky pad is only really good for a single use, after that the DPT will not stick properly to the case. There is an adhesive that you have to peel off that allows you can lock down the DPT into the case and then it will be stuck. If you do not remove the adhesive the e-reader slips out of the case and is not firmly held in place.