Self built handhelds (Yarh.io and others)

After the Steam Deck, I am watching modded handhelds with interest. To my surprise, there is a growing community of people who are interested in building their own, and sharing their process and what parts they are using. With 3D printing more accessible than ever plus available PC parts, creating your own machine is not as difficult anymore.

What they are building isn't necessarily suited for gaming, but a handheld PC that is not a smartphone. With the old tech and tinkering enthusiasts here (who might not like to use smartphones as well), I assumed this might catch your eye:

These are by Yarh.io, which showcases and sells Raspberry Pi based handhelds while also sharing the sources and details on the projects.

I stumbled upon it because of an article written by someone else creating their own handheld using the information Yarh.io provides - the Decktility by ByteWelder:

It might remind you of the Blackberry smartphones back before the iPhone 

Do you know of any other self-built handheld projects or attempted to build your own? 

What amazes me personally is the potential to create something smartphone-esque in terms of portability and on-the-go checking of resources (if you choose to build in cellular, and GPS for maps/nav), while not being hindered by either software or existing hardware in your device. You could have USB ports, other ports, and maybe a headphone jack, regardless of what is currently offered on the phone market, running the stuff you want and having the layout and size you need.