https://www.olimex.com/Products/Retro-Computers/AgonLight2/o...

Or with keyboards: https://wildbitscomputing.com/

https://www.kickstarter.com/projects/spectrumnext/zx-spectru...

Or you can go mobile: https://www.clockworkpi.com/product-page/picocalc

https://andywarburton.co.uk/post/gr3ml1n-a-compact-handheld-...

And if you want a real challenge, the one euro computer:

https://www.olimex.com/Products/Retro-Computers/RVPC/open-so...

I have been playing around with a per scanline generated display on a rp2350 outputting to a tiny LCD. I think there's potential for some pretty fancy stuff on HDMI. A 2350 with PSRAM, HDMI connector plus a MicroSD for bulk filesytem, and USB for input could be quite a fun micro PC.

I would be tempted to make somthing that had a second RP2350 with its own PSRAM sitting unutilized just as a temptation to users to figure out how to get more out of the gadget and learn about different multiprocessing architectures.

One of these https://www.waveshare.com/core2350b.htm

With one of these https://www.waveshare.com/rp2350-matrix.htm

Mounted on top, and an HDMI connector squeezed in somewhere,

I am a bit reminded of what GeoWorks Ensemble managed on a 640k 8086. Theoretically you could make a tiny system like this do even more.

It's a BASIC interpreter/OS for the RP2040