We have a similar trick for that, take the jpeg and split into multichannel, which gives you the 4 grayscale channels for C,M,Y, and K. Take each grayscale and convert to bitmap, using the halftone option, set your linecount, angle and dot shape, then set the Output Resolution to 1200 ppi. That makes the dots come out at a much higher resolution, even though the original was 72 ppi.
Steve