Great articles. I'm just starting to get into the hang of vi. I'm giving vi-mode in bash a go (with "set -o vi") but there doesn't seem to be any indication of when I'm in command/insert mode. Is there any way to see this?

There is a workaround in zsh http://superuser.com/questions/151803/how-do-i-customize-zsh...

The vi-mode is actually provided by readline, so bash has no knowledge of it. So, no.

I don't know of a way to do it.