Can you purchase one for HO scale? If so where can you find and purchase one?
You'd have to post this on the Model Railroader forums, and I have no idea where the 'best' place to post there would be.
Note that until you have actual scale power sliding doors, duplicating the lights is simply a matter of putting small LEDs or fiber-optics to a clear lens with some overpainting. With opening doors, multiple light sources interlocked to the door or its mechanism.
I doubt there is anyone actually manufacturing 'kits' for these lights (or for conversion to working doors on passenger trains) but the actual light itself doesn't seem to me to be difficult to scratchbuild.