Alright, found a 3D model of the Ikea 365+ 10.6L container that everyone uses as filament box. However, it did not have a modeled lid, wich was exactly what I wanted.

My measurements are close, BUT not super precise, so don't complaint when I share the model, when reality is you should NEVER design something tightfitting for plastic containers like this, without a real life reference.

Now that I have the lid, I can model what I want to do to turn this into a rael filament box.

Alright, modeled a pair of 1Kg spools from my go-to filament brand and set them up inside the container, as high as possible (so there is space for the dessecant at the bottom) and to the rear, so the filament can have a softer path to go to the outlet (wherever I put it, still undecided).

Things I know I DON'T want:

Drilling on the container body. Ever tried drilling those things? The plastic will shatter like crazy and drills will grab and pull like a velociraptor, and that's made even worse because the sides are at an angle, and drilling both the same is a pain in the ass.

#3DPrinting

Loose things inside the box (apart from the dissecant).

Roller carriers that are just sitting inside and can move and wobble around are just a no-no for me. It's just a matter of personal preference, nothing particularly wrong with it per se.

@Nixie

This idea is dead sexy.

For the troubling holes (I hear you, with the drilling), I can think of 2 reasonable options:

1. Soldering iron - melt the hole, directly on the Sharpie marks you've made on the side for precise location.
2. Dremel grinding bit that's pointy on the end. Same story as the soldering iron, it'll burrow in using mostly heat, probably.

Hope I'm being helpful/useful.

@kelvin0mql

I'll just avoid working on the container altogether. If I break something, it'll be lids, wich are much cheaper than the bodies.

But thanks for the advice ^^