PTAssembler is another potent application with a great tool set for 'tricky' stitches. One such use is employing it's Hybrid Rectilinear output projection format to correct for cosine distortion near the edge of an image. Once in a while I have no choice but to include a lamp or bowl in an interior shot and I use this to reduce the distortion along just that edge of the image to bring things out of the ultra wide angle look, whether the image is stitched or a single shot.