That's alanW6's car. He owns Speed of Sound. PM him. Incredibly helpful guy. They're a custom jobby, though. To my knowledge, you can't buy them 'off the shelf' anywhere. Otherwise, Im sure I'd have a pair. I actually PM'ed in regards to this same issue. He's extremely busy though.
There once WAS a company that made them, but they defunct before those cars came out. If you e-mail Alan, though, he may make a set for you. He's a hell of a nice guy.