Hi 24v, nice reading from you. It's a good thing that you shared your design! While reading my comment, it may have sounded a bit harsh, sorry - did not mean it. As I said, I did print your creation - and it's right there on my desk as the tool box.
I've just recently started to explore and try Thingiverse parts, not sure what is the usual workflow here. Once the parts are .STL, there is not much that can be done to change it, is there? At least not on my "Solidworks universe". Maybe if the editable solid parts are shared as well, others can make changes...
I would consider a separate "under the printer" rod IF there is the desire to restrain movement of the box along the side of the printer, with some sort of fitting to the "main box" - in a way that you could actually place the tools closer or farther from the front of the printer "as desired". And on the box itself, would make the openings a bit bigger, or try to find more room for "other generic pieces"... I just feel that there is some "plastic filled" regions that could have a practical use.
All the best on your designs - I'm sure you enjoy doing that as much as I do.