I'll bump this for no other reason than I'm hoping the same thing. With luck, all these third-party keyboards that will be released will include Dvorak versions. Can't imagine it would be all that hard to do.
And another bump... has anybody found one yet? I haven't.
As an iOS developer I'm prepared to create a Dvorak keyboard myself if I must but I'd really rather use someone else's. I have too many projects going on already.