Vim works great in Dvorak. I switched to Dvorak, and jumped right in to relearning my Vim keystrokes with it. After a few weeks, I was back to normal in Dvorak, in both typing and Vim.
For a while I used Qwerty for insert mode and Dvorak for command mode, but eventually I ended up using Dvorak for everything. My particular hand pain didn't show up until years after I took up Dvorak. My problem is mainly with my pinky fingers, and Dvorak actually seemed to be worse than Qwerty for me, so I've switched back to Qwerty.