Yes, create a UIImagePickerController from code, adjust its properties, add an overlay onto it, and with you controller, control whatever you want on that overlay : custom controls, overlaying images, etc...
That gives something like this :
self.picker = [[UIImagePickerController alloc] init];
self.picker.sourceType = UIImagePickerControllerSourceTypeCamera;
self.picker.cameraCaptureMode = UIImagePickerControllerCameraCaptureModePhoto;
self.picker.cameraDevice = UIImagePickerControllerCameraDeviceRear;
self.picker.showsCameraControls = NO;
self.picker.navigationBarHidden = YES;
self.picker.toolbarHidden = YES;
self.picker.wantsFullScreenLayout = YES;
// Insert the overlay
self.overlay = [[OverlayViewController alloc] initWithNibName:@"Overlay" bundle:nil];
self.overlay.pickerReference = self.picker;
self.picker.cameraOverlayView = self.overlay.view;
self.picker.delegate = self.overlay;
[self presentModalViewController:self.picker animated:NO];
OverlayViewController is the controller that you must write to control everything you add onto the overlay.
pickerReference is a property you can keep to send orders to the camera. For example, you could call the following from an IBAction coming from a UIButton placed onto the overlay :
[self.pickerReference takePicture];
