Really ? heard from a colleague that this will get you a likely refusal during the apple store validation process when deploying your app (said they were looking for storyboard files for each and every screen or something). Must have been wrong :-)

Though I think you're still stuck with xcode ? can you use a CLI toolchain (directly calling clang and so on) to compile, build and sign an IPA ? from the little I've seen of Xcode, it sucks (a lot): random crashes, GUI & behaviour inconsistencies, bad file management, etc...