Sorry if this is silly but today I have discovered that my (pricey, I know) Ergodox-ez keyboard (but I assume any other "programmable" keyboard should work likewise) allows for any key to be programmed either for "press" or "hold".
And after more than a year using an uncomfortable configuration for my wrist (I use emacs a LOT), I have set 'j' to behave as CTRL when hold.
And then my mind has blown up.
No more weird thumb positions, or elongated pinkies.
I had done this with one of the large thumb keys for space when pressed, Meta when hold, but I had never imagined using 'j' (or, say 'f') for that.
This essentially puts both Ctrl and Esc in a comfortable position on the home row, probably my favorite "ergo hack" ever.
[1] http://www.hammerspoon.org/