As it turns out, the empty space between the Alt and Ctrl keys seems to be there for a reason:

On a real keyboard, one with real key travel, if you don’t put your hands on some kind of padding, the meaty side of your right hand will fit in this space!

I learned this when, on a whim and with only one usable keyboard left (a sad Model M) I picked up a little 82-key AJazz AK33 board. This board sports the modern world’s unserious attempt at approximating buckling keys – Cherry Blue-esquers. But, hey, it’s small. Or something. And lighted. And has some key roll-over.

But it didn’t work for me. Turns out, my right hand would push the left arrow key at random – usually when hitting a burst of keys.

Luck was good, though. I got one of my ~30 year old NMB buckling spring boards working again. They aren’t the best keyboard ever made (i.e. an IBM AT board), but they are up there.