Maybe Pause should just trigger a batch file. Users could run any apps they might want, and go back to the game whenever they exit the batch file.
Users could even create custom "Pause Menus" to run inside the batch file. "Johnny 5" "History.Dat" "High Scores" "Tips & Tricks" etc.
There's really no limit to this approach- Want to call up a .jpg of the Pac-Man pattern you're trying to learn during game play? Allow the default "pause.bat" to be superseded by "Pac-Man_pause.bat", and have links to the patterns in "Pac-Man_pause.bat".
Another upside to this approach, is that other, non-PowerMAME coders can work on pause menus, freeing up MikeQ's time, and allowing people who can't code C, but can write a batch file, to contribute.