Edelkrone's SliderPlus+ is a slider that adds a long slide in a smaller compact size for travel. The design allows you to achieve a 2ft slide on a 1ft slider. At NAB2013, they were also showcasing an auto targeting pan head that will maintain a subject in frame while the slider is in motion. This unit can also be combined with their future motorized time-lapse controller for more interesting dynamic camera movements.
Up close, the SliderPlus+ has an amazing build quality and offers very smooth fluid movement. It can be used on a single tripod (or stand) if you can provide a wide enough stance to maintain support as the slider travels towards the end. Edelkrone SliderPlus+ sliders on eBay can be (Found Here).
Edelkrone SliderPlus Compact Video Slider