I want this (AutoHotkey), but for Mac.

Use Caps Lock for Hand-Friendly Text Navigation

Makes a lot of sense, seeing how Caps Lock key is kind of a mode of its own: A crazy screaming person mode. Now, let’s make it make it to be awesome text edit mode.

For now, I’m going to use it as a backspace, as I wrote earlier. The only problem with this is that I’m going to probably start accidentally capping things if I’m using someone else’s computer.