Hey Buttkraken,
When I saw people doing Whirlwind Earth Turns, I initially didn't spot the ET and just thought the trick went like that. Whirwinds with no Earth Turn are much more difficult in my opinion, as the ET kind of controls the tama in flight, whereas without it, I have to put a huge amount of effort into keeping the tama rising straight. It's the same with several tricks; I find it easier to flip from loaded tama grip into Lunar/Opposite Lunar than simply releasing the ken, as the flip gives some direction and momentum to an otherwise very fiddly movement.
If you're asking if's been done before, yes. If you're asking if the trick's legit, definitely so! If someone sets a Whirlwind with an Earth Turn in a game or comp, though, it stands to reason you'd have to put the ET in there too. Respect for hitting it, not an easy one at all!