They can be had from Business Cycles here.

$95 a pair, quite steep for a set of clip pedals. They have a very small platform and tend to be rather uncomfortable with non cycling-specific footwear. I.e., pinches, etc.

I have a set of Dura-Ace 7400 clips and like them a lot better than the RX-1's my friend has. The Royal Nuevo may be a nice direction to go, due the slightly larger size.

If you are using these for track only, then the RX would be a good option. Pedals are like seats though, personal preference rules.

-Pete