Well, I don’t know what is best, I don’t know if the commander x16 is the right choice, but something like it seems good. PICO-8 or TIC-80 (which I hadn’t heard of) are both interesting. I assume they’re both software, but I suppose that’s fine, as long as I can lock down the host… It’d be neat if there was an FPGA PICO-8 in a gameboy-like handheld form or something, with usb keyboard and mouse (optional).
I don’t know if PICO-8 is actually a sane ISA to implement, but it would be neat.