I believe that the Shadow Triad could be the Striaton Gym leaders based on what is written in the manga. In the manga, the Triad are not referred to by name, but by the masks they wear. The masks they wear are named after the elemental monkeys, which just so happen to be the main pokemon of the Striaton Gym leaders. I highly doubt this is a coincidence.
Feel free to make a new thread on this, because reviving threads that haven't been posted in for over a month is bad. :3 http://i.imgur.com/EkvQs.png