Most LED lights for cycling applications are predominately white for the front and red for the rear due to legal statutes. There are a couple amber lights available (or were- Sunlite and Dinotte), and there are a couple of even lesser available or adopted colors like blue out there.

A couple of theories of mine why the amber hasn't been as widely embraced:

-White and red are required by law. Any redundant set ups would also have to be red or white (depending) to be in compliance with the law if the primary light(s) fail.
-Battery management. Of course, USB lithium ions are the latest rage in bike lighting, so keeping up with spare cells is no longer a issue for some...
-The weight weenies and hipsters won't want 'em