Kind of, though in my testing Reachability seems to just hide the bottom anyway rather than having the app resize.
With things like this I just keep thinking about how much more potential we would have for innovation if handheld computers allowed the same kind of extensibility that all computers did 25 years ago. Today, only Apple, Google, or the OEM of an Android phone could enable such a behavior by explicitly providing an API for it (and explicitly blessing the software that uses it), so it just won't happen.
