A native Dvorak keyboard. There are apps to provide this, but the layout only remains in effect within the app. This is unacceptable, especially since every foreign keyboard you can think of is supported onscreen (and, be honest, most of these none of us will ever use regardless of your particular native language).
Also annoying in this regard is that Apple does provide hardware support for Dvorak. Why one platform and not the other? Makes no sense.
Now, I realize that there's probably no direct help available here. You have no more access to the OS than I do. If I'm wrong and you can help me, I'll welcome the correction and will sing your praises to Valhalla.
But at least you might be able to point me to the proper person to request this. It should be easy to include in the upcoming 4.0 update. What's one more onscreen keyboard among dozens. Thanks!