If you're looking for a super lightweight affordable motorized Time Lapse slider, here's an interesting Motorized 2-Axis Auto Panning Slider that was sent over from DigiSlider. The Auto-panning addition allows the slider to keep a subject in the center of your frame while in motion. Here's a video overview and a short Time Lapse sample towards the end of the video.
Unlike a basic motorized slider that has moves constantly, the DigiSlider Controller can be setup for true shoot-move-shoot settings. This allows you to work with long exposures as you can configure the slider to wait to move until your camera is done firing - preventing blurry images.
It's also possible to use the DigiSlider 2-Axis as a real time Auto Panning (parallax) video slider, and you can dial in different speed settings. But keep in mind that there is audible noise from the motor so it may not work well for interview settings or where audio is critical.
The design of the Auto Panning option is clever as it doesn't require a motor like other 2 or 3 Axis Motorized Sliders. This makes it very fast and simple to setup, but this design is also limited how far you can Pan the camera inwards to keep a subject in frame. Your subject cannot be too close for Auto Panning to work effectively (angle would be too great).
Also, keep in mind that this slider is setup with a motor and belt drive, so you cannot move it manually by hand. To move the slider it has to be connected to the Controller. Unless of course if you disconnect the belt drive using a basic hex tool, then you can use the slider by hand for times you don't need the motor, and you will still have full access to the Auto Panning feature.
DigiSlider offers a number of different Time Lapse and Motion Control Solutions, and for more information about this product, check out their website http://www.DigiSldier.co.uk (link)