Actually I had previously worked on an "experimental" feature that would let you run Magic from the command line, automatically export a movie, and then exit the program. It would need some tweaks to function properly for your purpose, but I think it could allow you to create a simple batch file or script that would work for bulk (unattended) rendering of multiple different projects. I'll have to take a look and see how much more effort it would need to finish it as a feature for a future Magic version, and/or if it needs some kind of GUI.
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