I ordered them from northeast motorsports in Ill (847.304.5515). they are one of the few distributors. front pads run $410 and the rears $287. these are endurance race pads that are widely used in 24 hrs of Lemons and such. so they are supposed to last the whole race. I figure they should be good for 6 track days at that rate. a bit costly but you probably make up for it with less pad changes.
"I would quote everything pixelblue said, but you've already read it. Take it from someone who's put the 1 through its paces"