Kevin, I know of no "dual color" LED automotive bulbs that would do what you want. I think what you would need to do is directly wire in LED PCB lights of both RED and AMBER in to the back of the rectangular fixture. Here is what I think would work:
http://www.superbrightleds.com/cgi-b...%2Fpcblamp.htm Note that you would probably have to cut in and extend the wires if you couldn't fit it all in because the base can not be clipped off (it contains the driver circuit). But I don't know if an amber array of LEDs behind a red lens is going to look anything but red -- you'd have to test it out to be sure.