Artofex diving arm mixers.
Diving arm mixers, from what I've read, tend to be slower at kneading, but don't heat dough up as much as other styles of mixers can. They also tend to come in really, really massive sizes, a small one will still have a 80kg capacity.
I've kinda got the urge to buy/build one.
Link below is a small almost home size replica.
Someone tried building one, but posts sorta fizzled out towards the end.
An Artofex PH0 would basically be perfect, but they're really rare and I'd assume absurdly expensive.