He said that the reason they don't do a violet Photon light right now, is because of lacking availability of a bright enough violet LED for their purposes. However, he said that this color is a frequent request, and that as soon as they are able to find one meeting their quality and brightness requirements, they'll probably be releasing a Photon in that color.
I would buy one as soon as they were released, if they made on in that color. Nifty. ;-)