A Raspberry Pi powered by something similar to the M1 or A14 bionic processor would be something. The Broadcom 1.5 GHz 64-bit quad-core ARM Cortex-A72 that powers the latest raspberry pi, is nothing compared to the new processor beasts from Apple.
An Ampere or other Arm server chip would fit the bill. Aside from Apple, no one is making arm chips to serve the laptop/desktop segment. So there's this HUGE gap between the endless sea of embedded/mobile Arm chips and then jumps to a handfull of mega-many-core server chips.
Apple is finally filling in one of the Arm gaps with a mid-tier chip that can handle a desktop load efficiently while an efficient GPU can handle graphics without thermally clobbering each other.
> Aside from Apple, no one is making arm chips to serve the laptop/desktop segment.
You can argue that their chips in this segment are not very good, but Qualcomm is actually specifically addressing the laptop market, and they're not "no one".
We already have the Mac Mini, but an A14-based SBC would be less of a stretch than an M1. A picoMac, so to speak? That would almost inevitably run MacOS by default rather than Linux, though.
The GPU is make or break for Linux. No GPU means it's just another server in a different form factor.