I've got an idea for a rail, tell me what you guys think. You get an H-beam, and build up some earth/snow at either end of it. It could be however high you wanted it to be, and have nothign underneath it. It would be flat and wide on top like a box, but have a cool and unique look to it. Not sure how well iron would slide, but maybe make it out of a different material or cover the top with something.