I've acquired a Hyperkeyboardpi[0] kit, not yet built. But essentially its a keyboard add on for a raspberry pi which when paired with a Hyperpixel 4.0 touchscreen from Pimoroni makes a little handheld terminal. It's designed for a Pi 3 but I'm trying a Pi 4. I'll see how I get on. The keyboard kit is only available in Japan but there are shipping companies that will forward it for you.

[0] https://www.telnet.jp/~mia/sb/log/eid317.html

[1] https://shop.pimoroni.com/products/hyperpixel-4?variant=1256...