Real stained glass IS practical in those applications. Our shop has installed dozens. It requires only some additional reinforcement to the light fixture box to support the additional weight.
What you are marketing is plastic pretending to be stained glass. What everyone else on this board is marketing is the real thing. We market something that looks like leaded glass. You market something that looks like plastic. I've been producing stained glass for almost 25 years and in all that time there has always been someone just like you trying to market their plastic imitation.