Dave, this is awesome. Really important stuff.
Have you built a CLI mode that listens for commands from BASE2 / BASE3 and displays them in the window -- maybe interprets them too (both raw code and human-readable info)? This would effectively allow anyone to reverse-engineer the different commands sent by the Legacy Bases when operated by any remote, or sent by your software.
Another potential use I see -- mapping special keypresses or sequences on older less-functional remotes to enable users to access Legacy functionality typically requiring CAB2. Essentially, someone with a CAB1L could fire off AUX3 on a Legacy-equipped steamer by tapping AUX1 twice within three seconds, for example. You could even use it to make your own hardware remote, or a software emulator of a CAB2. Etc.
Simply great work. Keep it up.