I remixed this case because I did not like the Nexus 5 writing. You can change the backing too a few shapes I programmed. The code isn't that great. Let me know what you think. Change to your liking! If printing with ABS be sure to scale x&y by 1%. Don't print in ninjaflex, the lower corners will separate.

You can change backing in openscad. Code is messy. Also you need to use either this or the original as a base to modify