The simplest and easiest 65816 system to buy is a Super NES or Super Famicom. I wonder if it mightn't be worth, at a later date, designing a cartridge for those things that turns them into something compatible with this kernel?
Just an idle, and probably batshit crazy, thought.
@elfi It's not so very slow; I mean, yes, it's less than half the speed that ÆSIR will run, but that doesn't make it worthless. A lot of the actual grunt work in ÆSIR is done by the ESP32 coprocessor -- 3.5MHz is actually plenty for game logic if it's not also shuffling bitmap data around like mad.