Juicedlink first introduced this slider idea as a prototype during NAB2011 (found here). The kit consists of a few different parts which are bundled or sold separately. The basic set will have at least a trolley (rolling carriage) and end clamps to hold a set of rods. The end clamps have three 1/4-20" threaded taps to mount stands. A benefit to this slider kit is that you choose any type and length of 5/8" rod you require. You're not limited to specifically choosing a 24" or 36" like IGUS or Konova sliders. With JuicedLink, you can carry multiple sets of rods if you want to run short or long. Suggested rails to be used are stainless steel rods for it's clean smooth surface and hardness, which run about $20 dollars each for 4 feet (48").
The setup in the video (above) is on 4ft. stainless steel rods with a few modifications done to get it motorized. This is pretty much the same equipment used on the motorized Konova slider by Vimeo member C Light. On one end I have a freewheeling Idler Pulley. On the opposite end is the servo motor, servo controller, and 4 AAA battery pack. These all simply plug in together seamlessly without any soldering to give you a reversible slow speed motor. For the string, i'm just using Nylon Mason Line. Fairly thin, but strong, and readily available at your local Home Depot. I decided on using Velcro at the ends so that I can adjust the tension of the Line. Below is the remaining parts list of what you'll need if you wanted to do this to other sliders.
Basic servos will not rotate 360 degrees. Here you'll find the Continuous Rotation Servo: http://www.hobbyengineering.com/H1429.html
You'll require a pulley to be mounted on the servo. This fits perfectly and has the proper amount of teeth to fit flush: http://www.servocity.com/html/pulley_wheel__futm2045_.html
To control the speed and to make the servo move in reverse, you'll need the servo controller: http://www.servocity.com/html/dual_servo_driver.html
To power things up, you'll need a small battery pack. This battery pack will simply plug in to the controller. http://www.servocity.com/html/battery_trays.html
It's definitely a smooth slider, but the design means you'll need two stands to elevate it. It's important to get solid stands on each side if you want to minimize any rocking or swaying when used in windy environments. Especially if you're shooting with a long lens. Before you consider the JuicedLink DIY slider kit, you should check out some important information about the slider over at the JuicedLink website. He's started a 'CookBook' of ideas and tips about using the slider, and pointing out a few things to keep in mind when going to a longer set of rods. You can find more information and pricing on the JuicedLink sliders (click here).