Honestly, I’d be interested in even smaller builds. The Nintendo Switch got me thinking of it is viable yet, to build a portable PC-gaming tablet yet.
Two years ago I was considering to build my own PC, but in order to replace my laptop at the time I had the choice between buying another laptop, building TWO PCs for two locations with all the synchronization and software costs that come with it, or a highly portable PC – where the use of public transport meant that anything much larger than a 17" workstation laptop would be unviable. End result was that I got an Acer VX15 laptop after all, since even using external power supplies to cut down on the size, weight and internal heat production of the computing package proved hard.
I wonder if meanwhile parts akin to laptop internals are available for custom builds? Back then, especially getting the thickness down below 4-5cm was near impossible.
That experienced left me quite impressed with the Switch; The gaming performance is great, especially considering that the fan is barely audible under full docked load, even when standing right in front of me. (Fan noise was one of my original motivations for moving away from laptops.)