After using the Comfort Keyboard system [1] for about 10 years, I made the switch to the Koolertron split keyboard [2]. I'm a huge fan of having the left spacebar programmed to backspace. It comes with extra key caps so you can make them all black.

http://www.comfortkeyboard.com/keyboards_ergoflex.html

https://www.amazon.com/gp/product/B076FTNXDX/