Actually, I've been thinking that it would be possible to make a an actual working wristcomp.
A Raspberry Pi or the like, with augmented reality glasses/goggles. Gesture recognition, a small keyboard and LCD, RF or WiFi modules, cellphone and camera stuff, etc.
I've seen ALL these things in different combinations for small form-factor DIY projects over the last year or two. Imagine all of them in one package? Such a wearable would cover, say, half the forearm, but could be made fairly flat.
The tech for a useful wristcomp exists now. Voice commands/recognition would make up for a lot UI issues, considering the form-factor; after all, you'd only have one hand to input information.
If I were a Maker, this is the project I'd be working on. Get it right, and you could leave your cellphone behind.
@thaj Well, since they don't actually exist, any usable computer on your wrist can be defined as a wrsitcomp. A smart watch could be even be, I suppose, though such gadgets are really stone age versions of what a Maker could build right now. Accelerometers for gesture input? GPS for location and augmentation details? The sky's the limit. Battery life could even be good, since you'd have the room to put down large ones (half-a-forearm).
@lostnbronx So Raspberry Pi 0/w for wifi and bluetooth, some sort of eink display (probably impossible to find), a small lipo battery/ charging circuit, a single ear bluetooth earbud with mic, @jezra 's Blather to handle voice commands, and a 3d printed housing (probably out of a semi-flexible material. BINGO - early 21st century janky hacked up wristcomp.
Once built and actually used in real life, continual tinkering/upgrades/redesigns would be inevitable. How long after that before an actual piece of cool-ass cyberpunk tech was on your wrist?