i wish we could just do that!
we use unix/linux/bsd- you use xmodmap to set qwerty/dvorak in those OSes. so you have to keep switching that way... in fact, i can't think of any OS in which you set qwerty or dvorak in the keyboard itself- all the ones i'm familiar with (mac, windows variations, *nix) set the keyboard mapping with software. so with your idea, we'd have two keyboards, but they would both be using the same mapping at the same time. not much help. (;