A friend has a Raspberry Pi with the all-in-one touchscreen case (stock picture above) which he had added more electronics to so the back cover would no longer fit, so I designed this in OnShape (https://www.onshape.com/) for him.
If you wish to modify it further, feel free - https://cad.onshape.com/documents/dfcc03c36904a3ec41cdc4ee/w/03d913ef9737bb219136bf0a/e/9b4f096591067c25a46ec6d2