Part III of iOS Unit Testing by Example includes some really cool refactoring exercises.
But first you have to spend 10 pages setting up a your Xcode project from scratch.
Since I had to do it, I thought I'd save you the trouble. Here is the complete project, ready for you to add unit tests and start refactoring. Just read the first page and a half of of Chapter 17, then skip straight to page 220 and begin the section "Replace the Difficult Dependency with a Mock Object."
Good luck! John Brewer