My one-box solution. 
SKB 12U pop-up rackmount ATA mixer case.
It is possible to mount 1 more elektron box into it, but you have to simply add spacers under rack ears of third unit.
It is better to have OT on the top of others as it has 2 lines of outputs and inputs.
Case is really big and has additional space for cables, psu’s and other gear inside.
Build quality is excellent and it is very easy and comfortable to use it. In case you are sitting on the chair you can raise all units to comfortable angle.
Another good option is that case cover can be mounted under the case itself and raise whole construction.
