I did one in a Robbo once as a demonstration for a student. I set the pedals to a pre determined position that gave neutral TR pitch (almost full right pedal). Rolled off the throttle and entered auto. At the bottom at the end of the flare it started to yaw left quite slowly and then more as the collective pitch pull came in. We touched down about 90 deg left of the original heading, so the key is to make sure you lose all ground speed. Either that or run it on at about max touchdown speed of 35 KT before it starts to yaw.
CareBear,
As per your scenario, I have used a very similar technique in the B206. Once established in the auto at speed, roll the throttle back on. Use only enough collective in the descent to prevent an Nr overspeed. During the flare and pitch pull, as it starts to yaw under torque, roll off the throttle to keep it straight and touchdown. Very controllable.
I think a genuine drive failure would be noticeably different to a simulated one though, due to the tail rotor still providing some stability even if it didn't have any pitch applied.