Just for fun designed a replacement battery cover for the D-3 Digivice toy and I think I got pretty close. The cover and the clip are separate parts so you could choose not to do the clip for a flatter back. The clip also might not sit too snugly into the slot on the cover so glue may be required. I am unsure on the durability of the clip so use I have no guarantees on if it would hold up with actual use as a clip.