I agree that it's a terrible idea to put a touch UI on a mouse-operated desktop and pretend you're done. That doesn't mean you always have to build two complete

I agree that it's a terrible idea to put a touch UI on a mouse-operated desktop and pretend you're done. That doesn't mean you always have to build two completely separate apps or UIs for each platform though. The differences between touch/mouse incarnations of basic components, such as lists, buttons, scrollviews etc. can often be resolved with adaptive design. Apple has already put the basics in place to allow for adaptive apps that scale from the smallest iPhone to the largest iPad. Doing the same for touch -> keyboard/mouse UI is not unthinkable.