I dunno, I think the ultimate hacker would sometimes reach over to the other side with her left or right hand. Split keyboards seem like kind of a walled garden to me.

Huh? I would think the ultimate hacker would use their tools with a bit of precision. Developers who use vim, for example, count the keystrokes:

http://vimgolf.com

https://github.com/easymotion/vim-easymotion