In 2007 I built a jib using materials and hardware from Home Depot. The jib can extend to a total length of about 16 feet. It uses circular wood discs at the pivot points to provide smooth, stable motion.
The jib works with a remote-control pan/tilt head that uses heavy-duty RC servos attached to external gear boxes. Both servos are modified to rotate continuously. The pan-tilt head can be supported from below or hung from above (the jib supports both options). To use the hanging mode without flipping the camera, the tilt module can be rotated 180 degrees.
The camera attaches using a custom mounting plate. Future camera rigs can use the same mounting system, so that the camera can quickly be moved from one device to another.
The jib can ride on a dolly I built in 2006. This dolly works with standard dolly track, including curved track.