Use ibtool
to manage your xib files. It's part of the command-line tools package one installs along with Xcode. While Xcode offers a GUI for editing the strings, ibtool
can be run from scripts.
Overall, Apple has some guidelines and advice for maintaining xib files; you can find their documentation here. Reading it, you'll find that ibtool
is fairly easy to use.
As impressive as the approach you've taken is (I've seen some truly awful ones in which every UI element had been connected to an IBOutlet just to effect localization!), it still winds up being additional glue code that has to be maintained (and believe me, you will wind up maintaining it as your needs change).
So as far as my two currency units go, I'd recommend sticking to localized nibs.