I'm sorry to say that no such as conversion kit exists, although I think it's a great idea. I would much rather see the shade instead of the light bulb.
I don't know what city you hail from, but I do suspect that there are lighting repair shops that might be able to do the work for you. They would need to solder connections for rods or lengths of chain in three locations along the inverted edge of the shade in order to distribute the weight properly. There are numerous companies that make inverted versions of the Tiffany-style fixtures. You could print out a picture to show them what you want. Or you could even buy one of the ready-made fixtures (I found some online for around $85) and then use their components with your shade.