I found a CDI controller... kinda. I found a seller with an official corded CDI trackball, and after seeing some YouTubers and Reddit posters say that everything was "perfectly playable" on the trackball, I went ahead and grabbed it. I figure if we get it here and determine taht it's unbearable to play with, we still have many options to get some more "real" controllers too.
Hoping I have time to begin my mad experiments to build our own tonight!