Pig Rails, wheels, and accessories are available at Boarderline. Pig Wheels is distributed through Tum Yeto in the USA and Ultimate Distribution in Canada.
Have you tried a set of rails on your skateboard deck? Rails used to go right on the edge of a skateboard since the boards were flat. Now with new shapes in skate decks they are usually mounted toward the centre on the deck. Doesn't look right but if you actually want to board slide on your pig rails then this needs to happen.