Multiple cases makes a lot of sense to me as well. The monster case is neat, but ironically non-modular if you want to be mobile with (a) section(s) of modules. At some point it's definitely more economic to have one giant custom-built case, but I will probably never (even want to) have one.
That said... I'm currently working out this topic myself. I think my mind is currently at building a single row consisting of a primary chain sound. Then other rows are placed generally in their respective slot vertically (obv, this isnt hp perfect). scatter mults and other fx/utilities in the holes remaining 😉. I like the idea of building instruments over organizing by utility. Thats also tough to do when you have that swiss army knife module.
I'm a fan of arturia, so I ended up with a 3U and 6U Rack Brute. they are great, but now I'm kicking myself for not listening to the 'get 104hp minimum/row' advice I was given.