So I created the... GPC MKII. With slightly mixed feelings. Hear me out...
The original GPC was kind of a joke, I didn't really plan on making more. But somehow it was popular enough to do so - and I was humbled by and grateful to the eccentric, kindly, patrons that bought one (particularly the good folks of /r/cassettefuturism).
And then enough interest to warrant a further run... but even in the context of being handmade, making more wasn't sustainable. Part of the joke was that it is not a computer at all - just a bunch of blinking LEDs wired up in parallel; such LEDs are through-hole, which means hand soldering. The first run had me doing approx 10,000 of them, which was... enough.
To make another run feasible required designing a PCB that could be assembled with LEDs at the fabrication house... but that means regular, on-or-off LEDs. I realised - with a slightly heavy heart - that to match the MKI functionality (or lack thereof), I had to make it actually a computer. A 16Mhz, 8-bit, 2.5kb RAM computer (aka Arduino).
Try as I might, I could not resist some feature creep and added some additional modes... but stood my ground with the colours - no RGBs here, just 576 pure, warm, red and yellow LEDs.