It's somewhat strange to me that their tech journey is so narrative and ends up with a VM stack, rather than any kind of salvaged / repurposed hard tech. But then again, I'm probably on the forth side of the spectrum.
It's a good first step in that direction, the first attempt at permacomputing good enough to criticize.
(I'm new to eZ80 assembly so the project is going slower than it otherwise might.)
The AgonLight2 has 512K of RAM and a 20 MHz CPU which is more than enough for Varvara.
I agree that 8-bit computers of the era (e.g. Pet, Apple 2, C64, TI/99a, etc.) don't have enough RAM to give Varvara its own 64k of memory (though it wouldn't be hard to design a Varvara variant with a smaller memory space) but otherwise there really aren't major barriers. As far as permacomputing goes though, there are plenty of hosts out there with enough memory to comfortably run Varvara (anything 32-bit will be fine, most 16-bit computers would also be fine).
Based on my eZ80-based implementation I think any of the eZ80-based TI calculators with 128k or more of user-accessible memory could implement Varvara without major problems.
I also hadn't seen the AgonLight2 before.
One quibble, though: the vast majority of 32-bit computers are microcontrollers, and most of them have less than 64KiB of RAM. (My comment at https://news.ycombinator.com/item?id=44611710 goes into more detail about the popular STM32 family.) They would be perfectly adequate for a self-sufficient personal computing experience (most of them have more total memory than the computers I used to run Turbo Pascal on, just less RAM, plus their CPUs are 1000 times faster, and they can read and write SD cards) but probably not with Varvara.
A few of us have been discussing a modified Varvara spec that limits the system to a smaller amount of memory (e.g. 32k, 16k, or 8k). I think with a spec like that it would unlock many implementations that are not currently practical.