Something made me recall a hoax article I saw in PE or Elektor a long time ago. It announced a 1kW BJT and the accompanying picture showed a TO-3 style case that appeared to dwarf a wrench placed alongside it. Obviously they used either a composite image or a tiny special-purpose wrench.
In the late 60s and early 70s, manufacturers produced metal case
Ge. I think the power ratings went up to about 250W, maybe 300W,
Out of curiosity I just checked at the element14 site and they have two 400W types. What is/was the highest power rating ever for a production transistor?