This pic needs pulled from the article & first post, it is an older mini...
Next: How to replace the SSD.
GLWT...
We're back in the age of closed hardware design and custom chips.
No, that is truly coming in 2020 when Apple transitions to their own silicon...
That case was originally designed to hold a an optical drive and a 2.5" HDD or two 2.5" HDs. My hope is that the y used the extra space to improve cooling dramatically. My old 2011 Mini with Radeon graphics and two internal drives would run VERY hot when it was under load.
The original mini was also taller & had an external power brick...
based on that photo, looks like its storage is also user replacable (and easily!) with a standard NVME drive directly under the lid.
"That photo" is from an earlier mini model, it should be removed from the article & first post...
PikerAlpha, who to my knowledge has been working at Apple for a year or so, has said that RAM, SSD, WiFi, Bluetooth, and (!) CPU are all replaceable. Needs to be confirmed, of course. (iFixit?)
https://pikeralpha.wordpress.com/2018/11/08/mac-mini-2018/
He updated his statement...
Update: it appears that we have two different logic boards. Mine (internal one) includes sockets for RAM, CPU, SSD and WiFi/Bluetooth modules but end-user hardware not!
I think the options are pricey, but it is a pretty sweet machine, with the option for some real power under the hood...
The thing that kills it, if one want an eGPU, one gets a huge box on the desktop...
A MXM-format GPU card (RX580 or Vega 56) in a matching (probably taller) TB3 chassis would be the best way to go, here is hoping some ambitious third-party comes along to fill this niche...
As to the couple of references towards the G4 Cube, look to the latest keynote for a clue onstage...
There it is, a larger than life mockup of the new modular Mac Pro...
Modular means socketed CPU, RAM slots, M.2 slots for SSDs, & GPU in the MXM format...
We will know more next year...! ;^p