If you’ve ever tried stitching photos together to create a panoramic photograph you’ll be more than aware of the awful distortion between one frame and the next. That’s one reason why it’s recommended that frames overlap by at least a third.
There is so much distortion because the camera is rotated around using a normal tripod or worse still, handheld. The axis around which the camera is rotated is centered on the camera body usually, but a panoramic tripod is different. The center of rotation should be the lens of the camera, specifically the “nodal point” of the lens where light paths cross before hitting the camera’s film or sensor.
Make Blog links to a tutorial on building a panoramic tripod head for $10! That’s a lot more reasonable than what you’d pay for a head from Manfrotto or manufacturer. It probably isn’t quite as portable or nice looking though and you might have to invest in some tools to cut the wood and build it but it would be an interesting project.
If that’s too complicated, you can build a battery using a bit of wire, a screw and a magnet!