Yes, and I tried using AutoHotKey to use spacebar as a modifier. But it's too hard to avoid conflict with "actual" spacebar usage.

You definitely have to be careful with your left pinky. I've started "palming" the corner control, when possible -- even for things like C-v and C-b where you can catch the other key with your thumb.

I've also tried key-chord-mode, with strong but uncommon pairs ("fj" "fk" "dk" "dj") set as a prefix for a custom map. The jury is still out on this, mostly because it's hard to change my habits.