Take a look at this. Very clever idea, leaves me marvelling at how simple and obvious it is!
I'll certainly be keeping an eye out for these. Could come in very handy. Only hitch I can see is that you have to be filming on a completely flat surface, and on a gorilla pod you'll barely be knee high unless there's a table near you.
Still, do want!
http://www.kickstarter.com/projects/jj1/cineskates-camera-sliders
