Something that produces iPhone code out of Flex/Flash code and vice-versa? That sounds impossible (I don't know either one) but if it were, it could be cash cow, no?
It could be implemented as a flash llvm front-end with an objective C emitter. You'd also need to write a Flash VM in objective C, which I haven't looked seriously at but wouldn't be trivial.
Most importantly, a system like this would allow you write any application UI in Flash. A C developer, say, could then leverage Adobe's interface builders and the flex library without the need for disgusting hacks.