303 Precision QTVR Panoramic Head. Personally I find that too much gear to carry for most of my travel photography.
I have since found Microsoft's Image Composite Editor (ICE). It is a free application that produces panoramic images from sequences of photos. I have not had ANY failed attempts at this point with great quality TIFFs to show for very little effort! The most impressive performance was when it managed to stitched a 9 scene, 3 image HDR panoramic (27 images) hand held and each seam was spot on.
I have not read up about what it is doing behind the scenes but I think it was come out of the same Microsoft Lab effort that produced the PhotoSynth tool which seems to back calculate relative locations that photos were taken and uses the focal length to create a pseudo 3D model. Amazing stuff!
It is free however, there is a non-commercial limitation on its use so not sure how this limitation relates to microstock?
To use the tool, simply drag your images onto the workspace area of the tool and it does the rest. Once it is complete, you can change the projection that the images are reprojected onto. The "Automatic" setting for the "Stitch: Camera Motion" setting seems to do a good job most of the time.
The resulting image can be saved as a TIFF, JPEG or published up to a Photosynth
It is well worth a try given it is free!
Down load it from here