Its worth noting that in one of the US B200 accident reports that the pilot did maintain directional control despite full LH rudder trim.
Which incident are you referring to here, Old Akro? The VH-ZCR report referred to a B200 in the USA that took off with full NL rudder trim, but it too was uncontrollable and hit a building. Is there some other B200 incident you are aware of, but not the ATSB?
There was also a reference to a C90 King Air in the USA but that is a different aircraft and the rudder trim was set in the opposite direction (that aircraft was able to get back around and land mostly safely).
Note that full NL rudder trim is more hazardous than full NR trim on the B200, due to the aerodynamic "p effect" where the propeller thrust line is shifted to starboard, increasing the NL yaw moment.