Ya, I have the X Button on mine, it's sweet. I had to enlarge the hole a lot, and shove some napkin bits in the x button so it could activate the loader. I'll glue it eventually. Looks hott with the clear back plate too. Only problem now is that the button sticks out kind of far from the back plate and can be turned on a lot easier by being bumped around in a gear bag or whatever. Can be fixed though, just mess with it.
They also do sell aluminum and carbon fiber back plates with buttons if you want.