Someone requested I convert my CEN64-Qt launcher (here: http cen64.com/viewtopic.php?f=17&t=15) to work with Mupen64Plus. I've finally gotten around to it and added several new features as well such as GoodName support and column configuration. GoodName support requires the data directory to be set (to read mupen64plus.ini). On Linux this is usually /usr/share/mupen64plus. On Windows this is most likely the same directly the executable is in.
This is just a basic launcher that utilizes the console UI to do all the work. I've added support for most of the parameters that appear on the man page. I don't plan on adding much more to it but I am willing to entertain feature requests. I believe the main things missing are archive support and some sort of input configuration. The former I'll probably add eventually. The latter is tricky to do correctly, so don't expect it anytime soon.
...you'll probably want to remove the contents of the mupen64plus.app package to make them easier to link to. Just right click on it and select "Show Package Contents." Then copy the Contents folder out somewhere else. The executable is Contents/MacOS/mupen64plus. The plugins directory (must be set) is Contents/MacOS/ and the data directory is Contents/Resources/. Once you set those paths correctly, it should work.