What sort of accessibility does MSAA do? Bigger fonts, bigger mouse cursor, high-contrast-color-schemes, etc? Most of these things can be written into a program as options. Maybe in the next Tk version, when they are supposed to have theme-support, you could set it as a theme? For now, you might want to read "perldoc Tk::option" for tips on setting up an option file to be read by all Tk apps. Maybe there would be a way to convert the MSAA settings into an option file?