Update: I'm uploading pre-configured backplates and hooks so you can mix, match and print what you need without messing with the model in Fusion :)
This model is building on the original design by @Német István and my remix of it to fit the original Ikea SKADIS pegboard. Those two models are just components to include in your own design.
This model is an actual, usable part which you can tweak (in Fusion 360) to the size you need. It is restricted to one locking mechanism and two hooks. The dimensions of the back plate and of the hooks can be altered as follows:
Plate and hook tweaking:
Refer to the two screenshots to see what the particular user parameters control.
Printing:
Freeing the locking mechanism:
Update: v4 fixes a bug concerning the hook_depth parameter (number 6).
The author remixed this model.