Though I've never used the Twiddler, I did spend about a year using a different one-handed keyboard due to injury. It was a FrogPad. It's a fine device for typing out sentences, but perhaps not ideal as a code editor. I eventually set up a full-sized keyboard right next to the FrogPad because it just felt easier to hit certain keys and chords that way. There might be better one-handed keyboards out there for programming, but I'm a little sour on the whole idea.
During this time, I also did some experimentation with voice recognition. It worked really well when coding in lisps. This was over ten years ago, and I'll bet this would work even better now.
I also have experience with the Kinesis keyboards; I used the Freestyle—not the Advantage featured in the article—following my recovery for about six or seven years. Though it looks like a medical device, the ergonomics are excellent. The Kinesis is a better typing experience by about 1000x. I have since switched to the homemade Ergodox, but still recommend the Kinesis.
During this time, I also did some experimentation with voice recognition. It worked really well when coding in lisps. This was over ten years ago, and I'll bet this would work even better now.
I also have experience with the Kinesis keyboards; I used the Freestyle—not the Advantage featured in the article—following my recovery for about six or seven years. Though it looks like a medical device, the ergonomics are excellent. The Kinesis is a better typing experience by about 1000x. I have since switched to the homemade Ergodox, but still recommend the Kinesis.