This almost works for me - but if my rootController.view is (or has any subviews of) type UIImageView, the image is immediately expanded to 480x320, regardless of the original size of the image.
I had to add re-create the CGRect manually to restore the image to the desired size (larger-than-screen) and position (negative offset), like this:
myView.bounds = CGRectMake(0, 0, screen.bounds.size.height, screen.bounds.size.width);
myView.transform = CGAffineTransformConcat(myView.transform, CGAffineTransformMakeRotation(M_PI / 2));
myView.center = window.center;
CGRect myFrame = myView.frame;
myFrame.origin.x = 0.0;
myFrame.origin.y = -400.0;
myFrame.size.height = 1281.0;
myFrame.size.width = 201.0;
myView.frame = myFrame;
Now, it works

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My thanks to those who have come before me!