http://www.youtube.com/watch?v=rlI9P2mkeOU
http://www.youtube.com/watch?v=3uhSWl7h ... re=related
This last shows what he's using, they look a lot like the small slides that Will Ray uses. It'd still be pretty easy to cut up some pipe to make them - schedule 40 1/2" maybe? I've fooled around with something like this, but it's nice to see somebody taking it seriously.
http://www.youtube.com/watch?v=0cfzuJwASyE