I also am about 90% happy with my Kinesis Advantage keyboard. I’m something like 480% happy with how long it’s lasted - seriously, I think I’ve had the thing for 15 years or something; I can’t even connect it without special adapters, because nothing has PS2 connectors anymore.
Looking at slide 6, on the left just below the Kinesis keyboard, was one that looks like it might actually address some of the 10% remaining dissatisfaction with my Kinesis keyboard - it has a proper numeric keypad in the middle, and proper full size function keys. A bit of searching reveals it’s a Maltron dual hand keyboard. The one in the slide doesn’t have it, but Maltron do have one with a trackball in the middle.
The remaining dissatisfaction that I can see - the shift keys are still stuck under the little fingers, and for some reason they’ve put the alt and control keys back at the bottom of the keyboard rather than under the thumbs.
I found their website to be a bit difficult to navigate, but there’s plenty of information there if you poke around a bit.
