A Personal Experience
Another option is to shot in vertical or portrait position. Pros: height will be larger. Cons: you will need to take more overlapping picture in order to get the width that is created in horizontal mode.
The following is a panorama of the Teton Mountains taken in 2011.
This panorama was shot with the camera in vertical (portrait) position. It consists of five individual frames merged together in Photoshop. In addition, the individual frames were shot in 3-bracket sets with each set being merged together prior to processing as a panorama. There were a total of 15 shots taken to create this panorama. Originally this consisted of 7 individual 3-set brackets but I did not overlap set 6 enough to enable Photoshop to include it in the final merge. Had I been successful this would have consisted of 21 separate shots. I used a Nikon D7000 and a Nikon 24-70mm lens with a focal length set to 50mm. The final dimensions on this processed picture are 70 X 21 inches.
Here is another attempt of a panorama taken of the Grand Tetons. It consists of 5 vertical captures, taken with a Nikon D700 and a Nikon 50mm f/1.8 lens. In my opinion the prime 50mm lens works best for these types of shots. I also think this is a better composition than the one above because of the angle I was shooting at. It also, in my opinion, has better color, better leveling, and overall better balance. Aperture f/18, Shutter 1/160 sec and ISO of 200.
To shoot panoramas it is important to understand the "no-parallax point (NPP)", Unless your subjects are distant landscapes, it's essential to eliminate image parallax. Do this by positioning the optical center of the lens over the point of rotation. Really Right Stuff has a great web site for understanding this concept in addition to having all the right gear to be successful. Follow this link to their tutorial.
An alternative to Really Right Stuff panorama equipment is Sunwayfoto.