http://www.istabilizer.com/store/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/d/o/dolly1_other.jpg

Besides the iPhone. says it fits any of the 1/4-20 mounts ..and GoPro (but I did not see the adaptor)
$60. Cute idea but without much weight and skate wheels, you may need a track. Still...

Dolly (http://www.istabilizer.com/store/dolly.html#)

Jim