Will this functionality be available soon, or should I focus on developing a
workaround?
A Support for loading a movie into and playing it from RAM will not be in QTW
2.1. It is, however, still definitely on Apple's to-do list. For now, you can
improve performance by copying your small movie to a temporary file on the hard
drive. From there you can force it into the disk cache or DOS Buffers by
opening and reading all of it yourself.