The magic ingredience is the Logic Supply MC600 case. Riser from Logic Supply too.
It takes mITX motherboards. We ended on a ASrock z270 motherboard which gives Thunderbolt over USB-C for future expansion. The CPU is a i7 7700 i think, TDP 90W (don’t remember) which suits the case (Noctua NH-L9i) and powe supply. The CPU has Inter HD630 graphics which performs amazingly.
Then only drawback is the external power supply. Currently running on the 182W brick, which is huge. But I think we could have downgraded to 160W and had a smaller brick and a better plug.