There are surely people who perform this kind of service, but it has to be possible...
I also have an E3P and I'm a trit freak as well. I just took the light, checked it and I didn't find a place where there could be enough material to install a trit. I guess you think about the button, but the metal is just a cap and not a massive button, I fear that it isn't thick enough to install a trit.
The light is heavy and the walls feel thick, there's a plastic sleeve inside the light giving you a wrong feeling though, the walls are quite thin... :sigh: