The Dvorak layout doesn't prevent wrist problems.

Why not Colemak instead? Colemac is both more similar to QWERTY than Dvorak (so a lot of keyboard shortcuts like Ctrl+Z/X/C/V still works and also easier to learn) and more efficient.

  Why not Colemak instead?

I haven't encountered anyone who has recommended Dvorak after using Colemak, so I'm guessing he hasn't used Colemak.

I switched to Colemak when I was starting to have wrist problems and since then my wrists feel fine... So I really recommend it.

Any idea if it is possible to re-arrange the backlit keys on a MacBook Air? I used to use Dvorak before I switched to Macs with their pretty keyboards.

To me part of the benefit of typing in Dvorak is that I'm touch-typing all the time.

Don't rearrange the keys, just learn to type entirely blind.

Yeah, nearly all laptop keys can easily be rearranged. Just search online for a tutorial.