Something like this? The heavy stagger is great, 42 keys is almost perfect, but the thumb placement is -- for me -- horrible. Having to move my thumb to practically under my palm is just terrible ergonomics.
This thumb layout reminds me more of the ErgoDox variants, and is far better placement. Is there a layout close to this?
The Kyria is nice; that's what I originally had my eye on. The stagger is right, and while some of those thumb keys are placed absurdly far in, there are enough further out to be useful. I do like the knob options, although I'd never use them.
You know, after I set my sights on the Piantor Pro, I completely forgot about the Kyria. I'm just now seeing the Halcyon series with a load of thumb keys! Frankly, more than I could use; I'm not facile with them and find dancing between layers with them to be challenging, but it does give my a lot of positions to use whichever is most comfortable.
I think that's the winner.