These are two options for a top shelf for the Ultimate Drawer System.
They mount with the same M4 screws and nuts as the original system.
F3D file is attached if you want to make changes. I may upload an XL version as well at some point.
If you have a 400mm+ printer, you can increase the “unitsWide” parameter to create one that is 3 wide or larger. They should work fine, but I haven't tested them.
The author remixed this model.
New attachment for the top