Hi,
If you follow the facebook and twitter streams from Carl Galvan of Supreme Lobster, he is constantly pushing unique fish to the market. He worked with Mike G for two SkyFullOfBacon.com fish related short films. You get a sense there is a real effort to move new and unique fish into the market. Most of his twitter/facebook is aimed at restaurant chefs, who all want to be first, fresh and cutting edge.
I think their strategy is win acceptance by the chefs. which will then trickle down to the consumer level. However, it seems these fish aimed at chefs are not in large quantities. It may be they stay at chef-level.
Carl will occasionally mention some stuff will be at Dirk's, or other fishmongers, on a weekend. These alerts to the consumer are fairly rare.
Supreme Lobster did have one of their in-house fishmongers working hard to filet an Asian carp (which I understand is not related to carp) to minimize bones. I know these fish ended up with chef's to experiment, though I don't know if it reached retail.
Regards,