I found it hard to justify more than a whole kalax cube for Memoir 44, with the base game and equipment pack overflowing to another shelf.
I had a look around at 3d printed solutions, but nothing really did what I wanted it to do.
I was looking for a sleeved and accessible storage solution for:
FIRST BOX
I started with the base game and ended up with (clockwise from top left):

The second layer consists of:

(I printed the Badge and Token Trays with different colour text to distinguish the origins. If you do not like the specific Badges Token Tray you could replace this with a generic tray (1 9v2 BTSmall.stl)).
The third layer is filled with:

So, the first box was done.
The New Flight Plan was stored in three trays and a deck box;

The three New Flight Plan Trays fit into the Spacer Tray in the base box;
The deck box fits into the spare deck box space or replaces the blank deck box in the base box.

So, then I had the Base Game and the New Flight Plan in the base box, and an empty box.
SECOND BOX
The first layer of the New Flight Plan box consists of (clockwise from top right):

The second layer consists of:

(I printed the Badge and Token Trays with different colour text to distinguish the origins. If you do not like specific Badges Token Trays you could replace this with a generic trays (1 8 BTLarge.stl)).
The third layer is just big enough to store all the manuals from;
So that left the Equipment Pack Box as the third box.
THIRD BOX
I started with a frame for organisation (3 1 Frame.stl) which requires a print area of 235mm x 250mm. I printed with an internal brim, and this remained on the print in the box.
Then came the drawers for all the miniatures from the Equipment Pack, the Battle Maps and the anti tank guns from Mediterranean Theatre. I used the badges that come with the game to label the drawers. I had to make a few badges that did not come with the game, but I ended up with:

Then I printed deck boxes:

The top layer then has room for the Winter/Desert board or the base game board if the winter desert board ends up in the base game box.

MODULARARITY
There is some level of modularity. If you only wanted to take one box, the Army boxes can be swapped around. Terrain boxes can be swapped around. Badges boxes can be swapped around. Deck boxes can be swapped around. Boards can be swapped around.
Similarly, the layers can be moved around, for example if you do not use the card holders and the badges and tokens for the campaign books or battle maps, you could put those on the first layer of the second box, with the armies on top to make the things you use more accessible.

STORAGE CONCLUSION
I have heard that some people get the battle maps into the boxes, but the way mine were folded, they would not fit.
I ended up with three boxes containing:
And the miniatures, cards, badges, tokens and manuals from:
I store the Battle Maps and the Breakthrough Board outside the boxes, which leaves me with all my Memoir 44 stored in one Kalax cube, with space to fit another standard game box. I calculate this as a space saving of over 40%, and things are now more accessible.
This model was to solve my specific storage needs.
I hope you can get some benefit out of this model too.
If you do, please let me know.
The author marked this model as their own original creation.