I have some duplex outlets where one of the two receptacles is on a switch. I wanted to install the one on the switch upside down (ground up) so that it's easy to tell which one is on the switch. Unfortunately, I'm not sure a device like this exists. How can I make the switched receptacle different?
I suspect that you are way way over thinking this issue. Lets just say that you were able to purchase a duplex outlet that looked like this:
...And then you decide to wire it up such that the outlets with the safety GND hole UP would be the switched outlet. That would require you to remember that this orientation was switched. It would turn out that this would always be on the bottom side of the duplex. So why not just use normal outlets and simply remember that the switched one is on the bottom.
If you really do need a visual indicator then get some acrylic paint or nail polish of a likable color and paint the surface of the switched outlet.