I built a Dactyl Manuform recently (https://github.com/tshort/dactyl-keyboard) which seems to have keywells like the Kinesis Advantage, and it's been fantastic.

I 3D printed the default case in the repo - I'm yet to start poking around with customising the parameters and OpenSCAD but eventually I'd like to be able to make the case to fit my hands perfectly (as it stands the default thumb cluster on the 5x6 keyboard is a bit large for me).