Have you ever heard of Cineskates? They are skateboard like wheels with special mounts that fit on the Joby Gorillapod Focus made for dslrs but there is no reason you can’t attach this to a Contour+, Drift HD or GoPro Hero.
Check out the Cineskates slider dolly wheels review.
Our sister site bought the first one off the line from the company and did a full unboxing and overview of the Cineskates in action. With these wheels you can do super smooth tracking and dolly moves with your camera. Check out the video in the review for an example of what you can expect with the Cineskates. We shot this with a Canon T2i with just the kit lens. Amazing what smooth motion can add to your videos, making them look more professional.