As I've mentioned before, I do freelance work as an iOS developer. This is, of course, awkward and painful as a Vim user because it can be a challenge to work productively outside of Apple's IDE. I like to keep tabs on resources for working with Vim and iOS/Mac development, so here's one of my latest finds: a detailed post by Benedikt Terhechte about using Vim as an Xcode alternative. The author explains how to install Clang Complete, and some additional libraries like surround.vim and ios.vim.
The Carbon Five blog also has lots of resources for working with Xcode outside of the GUI. Building Xcode 4 projects from the command line has some help for dealing with
xcodebuild, although if I remember correctly I last got automated builds working by following this answer on Stack Overflow.