Such "genetic tinkering" is being done on the northeast coast of the
United States with Pecten irradians, but I haven't heard of any similar
effort with Chlamys islandica.  I suspect it would be more difficult
with C. islandica since it inhabits cold, fairly deep water.  Pecten
irradians lives in relatively warm, shallow waters, and is easily
cultured.  I have seen some of the genetically engineered specimens of
P. irradians, in bright orange, yellow, and purple, specifically bred
for use as a garnish on dishes at upscale seafood restaurants.  They
were originally exported to Japan, then caught on on the west coast of
the USA, and now are becoming popular in some other areas.  The shells
of these engineered scallops are not only more brightly colored, but
also thinner and more fragile than the shells of "typical" P. irradians.
 That wasn't the intent of the breeders, just a "side-effect" of the
genetic alterations that were made.  C. islandica is quite variable in
color, even without genetic engineering, and in general is a more
colorful species than P. irradians.
David, I'd like to see your images.  Thanks.

Paul M.