I'd be happy to upscale your music video to HD for less money than it would cost to print to film and re-digitize it. Essentially, you just want to upscale it about 10% at a time, and apply some sharpening at each step. Using bicubic interpolation, you'll get decent anti-aliasing, but you'll see a definite softening of the image. There are also complex (slow) scaling tools that use vectors, thereby detecting and enhancing lines and edges as they upscale. Depending on the subject matter, they can do a pretty good job. No matter what you do, you never get something for nothing, so printing to film and rescanning is going to introduce more losses and will still produce a soft image.
Doug