There may well be examples of this, but while the blind developers I have known (a small sample, I admit) typically use screen-reader technologies to navigate and read code, they use a keyboard to write and edit it.

I don't disagree with that. I just meant I don't think it's going to have mainstream appeal. A wheel chair also makes a disabled person super productive if the alternative is not being able to go anywhere at all, but it doesn't make wheelchairs super appealing to people with healthy two legs if you see what I mean.