There is a workaround you can do with non stackable items:
0) start the game and the trainer (trainer with root privileges)
1) in game, enable the trainer (F1, you have to hear the robotic voice "trainer activated") select a stackable item with mouse
2) in trainter, replace that stackable item with 1 non stackable item that you want.
3) go to rest at bonfire and open the item box
4) get up and look at the inventory, that item now has not an icon, just leave it on terrain.
5) pick up the item (it's broken) and go to repair it.
I made this with latest patch and calibration. All three DLC.
Nice! It works in your way.