There is Minuum, with a pretty fascinating one-row keyboard, and it worked pretty well by then! Sadly it is pretty much dead (no update for three years)and work

There is Minuum, with a pretty fascinating one-row keyboard, and it worked pretty well by then! Sadly it is pretty much dead (no update for three years)and worked pretty well. However keyboards have vastly improved in the last 3 years, and not having updates is really an issue nowadays.