Do you need bread bins for this? Or do the systems fit laterally into shelves in racks? If that is the case, this can open up many more options for you.
As a general rule, the "normal" intermediate tower is mounted laterally (and it must be straight, otherwise you are pretty bad). take 5u (4u for the midtower, 1u for the shelf, unless they use shelf rails, even in this case it's usually a little over 4u). For most people who install cabinets, they do not want to spend so much on shelves / cabinets / etc. they do not use it properly.
Bread bins are considerably more economical, usually 1/10 of the cost of cabinet installation for perspective. Of course, it is only the cost of the initial mounting hardware (shelf / rack / cabinet / etc.), but the users do it in volume and configure it to handle it (and usually everything is density / lower configuration for this).