I highly doubt that a xeon cpu could be soldered.
The « magical » proprietary connector that would alow the « brainbox » to power multiple gpu...
well if you take a quite resonable scenario for a workstation you are looking at 1200w...
so I dont see how the could fit this in a « brainbox » the size of a mac mini or little bigger... would be massively bigger... other wise their conectors would need to carry live 220v pass tru if each module has his own psu ....
I dont even know if it is legal to have live 220 ac power on a proprietary connector.
but stackable modules are totally possible if they got their own psu and power cord.
If there is a proprietary conector, it will be a sort of pciex16 via thunderbolt and there will be 2/3 of them... and there will be a pcie switch in the brainbox to handle the lane distribution...
no one is going to buy a « storage module » that only have a m2 slot.
so to be able to « store » something it would be at least 2/4 m2 slot.
but more realistically they will probably do their own stuff with welded on ssd.