After seeing timelapse sequences other people had created that introduced camera movement I knew I had to build a timelapse camera dolly or camera slide. I had a project to make a 3D printer which had stalled - after a fun morning dismantling it I had a fun afternoon re building it as this Camera Slide. It makes use of the same electronics and motors as used on a Reprap type of 3D printer. The coding and electronics can easily be adapted for use with any Arduino and a stepper motor driver. The STLs provided here will allow you to make a similar slide of any length you wish.

More information and the coding and electronics are detailed on my website:
https://www.techmonkeybusiness.com/articles/Camera_Slide_Project.html

Now that I have a timelapse camera slide I just need to get out and about (preferably into the mountains) to make use of it. Here in windy Wellington (NZ), the clouds move so fast that timelapse photography is not needed.

March 2016 - Update I have designed a better version. You can find that here: http://www.thingiverse.com/thing:1419236 or if you want absolutely all the info and a few more diagrams and images, go to my website here: https://www.techmonkeybusiness.com/articles/Camera_Slide_Projectv2.html.

The 3D printed bits were from a grab-bag of bits from an aborted 3D Printer project. If I recall correctly they were all printed at about 15% fill, with double layers on the top and bottom surfaces and all outside perimeters being two layers thick.

Full details on the electronic circuits and Arduino code can be found on my website:
https://www.techmonkeybusiness.com/articles/Camera_Slide_Project.html

The design includes some panels which can be cut from medium density fibreboard or acrylic. The TurboCAD, DWG, and DXF files that could be used for laser cutting are on my website.

The rails are 16mm OD Aluminium tube, and the drive screw is M8 threaded rod. The design is such that you can make the slide any length you like. All you will need to do is change one parameter in the Arduino code to reflect how much travel you have available.