This sounds pretty neat; a handful of modest little adjustments that could prevent a lot of headaches. Being able to instantly take Colemak with me to any computer would be amazing (although carrying a keyboard around everywhere I use a computer sounds iffy).
Now I've said some positive things, so I'm going to nitpick. This is HN, after all.
The first thing that stands out to me is that it doesn't seem like a lot of attention has been paid to ergonomic details. The lowest hanging fruit here, which I've never seen in any keyboard, is to put feet on the side toward the user. In almost all cases, the way I've seen people's desks set up is such that there is no way for them to have a neutral wrist position (wrists not bending up). Worse yet, keyboards invariably have those little feet on the back, and people assume they should use them, which causes them to bend their wrists up even more. Ideally, a keyboard would let you fine tune its slope so that you can set it up exactly to your needs, although I have no idea how you would build that conveniently.
The second nitpick is with something Atwood says on the linked page:
> Nothing lets you get your thoughts out of your brain and into words faster and more efficiently than a well made keyboard.
Technically that is true, in the sense that a stenotype is technically a keyboard. But the reason I'm picking this nit is that as someone who has made it a side quest to find something better than a standard computer keyboard, this is a bit of a sore spot for me. The minimum you have to be able manage on a stenotype to be a court reporter is 225 wpm for live testimony. That's a $50k/year job where a requirement is typing faster than the all time world record for a typewriter-style keyboard.
That's a phonetic system, and it's not immediately obvious how to untangle all of the issues with making it work with programming. On the other hand, there's Veyboard, which is non-phonetic and more flexible, and seems like it could be used for programming in its current state. It's slower than stenotype, but far faster than a traditional keyboard.
My point is that it irks me that we have so many people typing so much and getting injured, and not much focus seems to be going into adopting a better, radically different approach. We have a handful of very expensive hardware options intended for specialized markets, and we have Plover[1] (nothing similar exists that I know of for emulating a Veyboard), and that's about it. And on the mass market side, we have less expensive, specially designed ergonomic traditional keyboards based mostly on shakily researched principles.
Would it necessarily help with RSI just to increase typing speed? That needs to be tested. But it seems likely that if you reduce the amount of time spent typing, you'll reduce the amount of damage.
[1]http://plover.stenoknight.com/