I don't know much about digital art, but if you worked with many layers and can apply partial transparency to all areas covered by the glow effect, the most crurial problem is solved. Then you give it to an advertising company that prints on foil. Then you'd have to see whether luminescent foil (not sure about the term) is available in white. You then frame it with the printed foil on a transparent plastic or glass backing instead of cardboard and the lighting foil behind the backing. That should make the whole thing sufficiently rigid. The rest then is just about hiding the wire for the light foil.