I was able to get vuforia running with the Unity 4 beta by commenting out two lines in the Xcode project:
generated the error: AppController.mm:781:52: Use of undeclared identifier '_curOrientation'; did you mean 'orientation'?
generated the error: AppController.mm:781:52: Cannot initialize a parameter of type 'int' with an lvalue of type 'NSString *'
The app ran, recognized the target but the display was kind of messed up. Seems like it almost works as is though, any ideas on how to fix the above errors? Or, are you planning any new releases for Unity 4?