Anyways, regardless of all the scenarios I could come up with, I believe commands for the machine control panel should be able to be hot-keyed. This way, a separate peripheral input connected via USB would be capable of ALWAYS commanding the machine, without having to enter the control panel tab and use mouse clicks. Even PC mice have hot-key features of course and profiles that could be activated when printing. It would enable a truly "live" printer control at all times, GUI panel on-screen or not. Finally, by use of hot-keyed macros, one could add their own imaginative features, such as 'hold a print bed in place for 10 minutes', with the push of a single button on the control pad, or move an extruder head to a specific X/Y/Z position with one button press. A joystick could be used to move the print bed around at a desired rate; possibilities = endless.
This would be a great way to allow users to customize their entire setup and experience with the software control, with their own devices and their own commands on-the-fly.
Thanks!