Applying my observations from what I know to things I don't have any direct knowledge about, this is what I would surmise.
1. I would assume Lippert designs their slide systems for certain weight ratings (with a factor of safety built in).
2. Manufacturer's wouldn't install a slide system into a rig that would exceed the manufacturer's weight rating for that slide system. There is no upside to doing that and could be very problematic (along with getting someone fired).
Beyond that, I don't know what your definition of a superslide is, but my TT has a schwintek slide in it that has worked flawlessly for 6 years, and it's a pretty big slide carrying a lot of weight.