Hardware to rotate a video signal 90 degrees? Okay, so what I'm trying to accomplish is to take a standard TV monitor and mount it at 90 degrees, while simultaneously rotating the source input signal 90 degrees so that the video output appears right-side-up on the rotated TV monitor.  

We're doing this in an attempt to mock-up a giant iPhone in portrait orientation, driving the screen image off of an actual iPhone in portrait orientation.  So the TV needs to receive the signal from the iPhone, rotate it 90 degrees, and then scale it to fill the screen (probably distorting it a bit due to different aspect ratios).  

I understand this sort of thing is relatively simple to do in software, but we really need some sort of hardware solution as we will be running this on a live feed, with the video running directly from the input device (iPhone) to the TV, with no computer in-between.  Is there any readily available hardware (like a cable or adaptor, maybe) that can do this?  Or perhaps any known TV models that allow the input image to be rotated arbitrarily?
I don't know of any cables which do it, but you have a simpler solution:

A few recent HDMI computer monitors will be able to do this in hardware - an example I quite like is the The Samsung Syncmaster C24A650X