I built this portable computer around recent mini pc with an Alder Lake N100 processor. With a 12th gen Intel processor this mini pc still has great performance considering the cheap price and low power consumption. Plus it's powered by USB C PD which is perfect for easily powering with a portable battery bank.
I wanted the final design to be around the same width and height as the mini pc (about 72mm x 42mm respectively). This limited the size of the display I could use but compromises had to be made to keep the "slim" rectangular shape I was going for. I picked up a 65W 20,000 mah USB C PD battery bank that would fit these dimensions. In many portable computers/cyberdecks I've seen the user input devices are built into the overall design but I decided to keep all input devices separate to keep the device from becoming too bulky and not limit the computer to a certain style of keyboard or controller. You could connect a full sized keyboard for programming or just connect a controller if using it to play games.
To keep the design as slim as possible I decided not to build a whole enclosure around the core components. Instead everything is screwed to a 6mm piece of laser cut ABS. The ABS frame also has a handle cut in one end to make it easier to carry around. The battery bank is strapped to the frame with a 3d printed bracket and the display is mounted on a hinge so it can be folded down when carrying around the computer. I was able to find really short and flexible USB C and HDMI cables for connecting everything together. The final design is really simple with only three 3D printed pieces, the laser cut frame, and a piece of clear poly-carbonate to protect the display.
At the last minute I built a little 3d printed hat that clips onto the top of the mini-pc. The hat holds a small uninterruptible power supply that allows the computer to plugged into two power sources to provide an automatic power backup. The UPS design uses two USC C PD trigger modules providing 12v to the UPS circuit. The output of the UPS circuit goes to the mini-pc and a small 5v stepdown module for the display power. Something like this seems necessary for the computer because there is no way to charge the battery and continue to power the mini-pc at the same time. Recharging the battery would always mean turning off the computer and interrupting your work. Now if the battery is getting close to dying, you can just plug in a second usb c power source and keep working.