Re: “A keyboard that includes a numeric keypad is simply not ergonomic when you put the mouse to the right of it.”, I saw these the other day: keyboard with separate numeric keypad, or with numeric keypad on the left for right-handed mousing.
http://www.evoluent.com/

All is not lost for DataHand: they say “We will soon have a limited number of new DataHand Pro II units for sale.”

I got a Microsoft Natural Keyboard when I first started to feel discomfort in my arms and wrists. It helped for a while. But ultimately, there’s nothing natural about qwerty or dvorak keyboards no matter how you curve them.

Dvorak isn’t a solution to RSI. Any benefits the layout brings will be negated by your tendency to use those benefits to type faster.

I swear by my DataHand. I had some reliability issues with my unit initially, and there’s quite a learning curve, but now I wouldn’t want to be without it. Unfortunately, it’s not being manufactured any more. You may find one on eBay.

Don’t know anyone who’s tried it, but this has always intrigues me as the most comfy alternative for your own mission control:
http://www.ksl.stanford.edu/people/kpfleger/ergo/
Armrest Mounted Split Keyboard Setup
Defnitely forces you to use the correct fingers on the correct sides of each keyboard.
And of course data gloves deserve a mention:
http://gram.eng.uci.edu/~cmehring/KITTY/about-kitty.html

Have been using Caps Lock mapped as ctrl with emacs and the OS cut/copy/paste keys in other apps for two years, very comfortably.
http://www.emacswiki.org/emacs/MovingTheCtrlKey
Instructions on swapping keys for Mac, Linux and Windows.

Using Caps Lock as ctrl keeps the pinky on the home row, rather than scrunching up the hand.

The swap makes the bash/readline ctrl-based keys much more attractive than reaching across the keyboard to home and end.

These work in bash, emacs, and most apps on Mac incl Firefox: Ctrl+a (beginning of line, ctrl+e (end of line), ctrl+s (isearch), ctrl+r (reverse search history etc), ctrl+k (cut/kill to end of line) etc.
http://www.gnu.org/software/bash/manual/bashref.html#Readline-Bare-Essentials

Firstly, learn Vim. Emacs will work but only if you do heavy key remapping.

Keyboard wise, the 4000 ergonomic is the step in the right direction, but it’s small time. Get a Kinesis Advantage Pro. Expensive, yes. Worth it? Yep.

Lastly, get the foot pedals. I don’t know if your foot pedals are compatible with the kinesis advantage pro though, maybe. In any case, all of these things combined, you shouldn’t be feeling any stress at all. But yes replace the 4000 ergonomic immediately. The only reason I keep mine around, is if someone wants to use my computer. They look at my Kinesis Advantage Pro and I can see the fear in their eyes at the premise of them having to use this “contraption”.

That’s another thing, you NEED to know how to touch type to use this thing properly, and even then it’s a slight learning curve. Totally worth it though.

I find some of these exercises help and have a regular reminder to take a break.

http://www.efuse.com/yoga/

http://www.praven3.com/workpause/

Did they do an MRI scan on your wrist? It could be a “ganglion cyst” that’s putting pressure on your wrist. These can be removed; otherwise, they do tend to shrink on their own if you take it easy on your wrist.

You may want to check that out.

Other than that, I’d like to put my vote in for the Microsoft 4000 Ergonomic Keyboard…

I don’t have a Dvorak keyboard on my desktop nor on my laptop. I use Windows’ built-in functionality to alter the layout in software.

-how do you manage if you have to use a QWERTY keyboard?

As Jart commented, I also can type about half of my normal speed by looking at the keys on QWERTY. At times when I’ve had to do it a lot, it’s almost like there’s a psychological switch where when I’m not looking at the keyboard I naturally type Dvorak, when I am looking, I naturally type QWERTY.