Passion II is actually kind of a setneck, as the neck goes up to the neck pickup, not to the tail.
I have had a MG Quantum ('91) that had no truss rod. It was introduced around 1995. What for, I do not know. I do have a Modulus Graphite Genesis ('99), which neck is a graphite skeleton topped with wood. There is a truss rod, but I think it is worthless. The neck is stable, like the other graphite necks I have, or have had.