Thanks for the excellent details. I'm considering using the VGA cable to my Pioneer instead of the component so I can have both x360 and xbox1 hooked up (has only one component).
A 1024x1024 plasma is an ALIS interlaced plasma, which is a dying breed (older tech). So its 1024x1024i and rectangular pixels are nothing "weird" at all in plasmas. Like 1024x768 for 16:9 screens.. there are plenty of those out there even the latest models from sony, pioneer, panasonic, lg etc in 43". 50" models and up come with 1280x768.
If you think about it, an anamorphic DVD displayed on a 16:9 CRT the way it was meant to be displayed, stretches the pixels of a 720x576/480 image resulting in rectangular pixels. Nothing new.