That is a pretty good point. As a rubyist, I always use and advocate two spaces - but if I ever find myself on a team with visual impairments, I'll be sure to ask whether tabs would be useful to the team. I'm a big believer that Team-level consistency is far more important than Universe-level consistency, and silver bullets kill.

That said, I'm intrigued - surely this must be a solved problem at this point? Anybody aware of any good text editors / editor plugins that allow you to modify the visual spacing of start-of-line spaces?