I don't know if I missed this, or this just showed up. Looks like E-Image is adding more products to their attack on the DSLR market. Here's what looks to be like a very effective camera slider using seperate linear guide rails. The carrier for the camera looks quite familiar to the 'guys in yellow and black'. This setup looks like they want to go long, calling it a video track kit.
The end plates require that you use two tripods to use this 'video track kit', and this design doesn't appear to be a solid setup for plain floor use. It's quite possible to make different ends with feet and legs to further make this a more versatile product, we'll just have to wait and see where they are going with this. For now you can try to keep up with the new products here: http://www.eimagevideo.com/enproductSeries.asp?fl=183