While it still wouldn't be easy, if I really needed a mirror ball, I'd create it in 3D. I'd start with a 3D sphere, create squares and place them in a band across the center around the wall, and duplicate them and rotate until the sphere is completed covered by them. Then I'd need to create the room around the sphere - to create what the mirror ball will reflect (floor, walls, objects - everything). Then I'd apply a highly reflective texture to the mirror wall. Then create lighting to light the ball and room. Once complete, I would trace the ball and separate from the room - then it would be ready to use in whatever graphic you needed it in. I'd probably have to put in 4 - 6 hours to accomplish all that.