Well the reason behind this post was because I was playing on my friends xbox360 on a Plasma. The 360 was set to output 720p and the picture didnt appear stretched at all. I'm guessing maybe the PD simply scales the image from the 360??? He was using Component video so I'll presume the 360 was outputting at 1280x720.
Hmm... so using that "scaling" theory, I guess I could run a PC game at 1280x768 to a PD and it should scale it accordingly without any stretching?
From what I have read the 720p signal is downscaled some when used on the 1024x768 widescreen displays. So you lose some res but everything maintains the proper aspect ratio. So it looks like it would work.