Just got off the phone with Sharp, again. This time I got a slightly more coherent answer, but still not satisfactory. Previously they claimed the only way it would do 1080p was with a terrestrial broadcast signal, which doesn't make any sense since there isn't any ATSC 1080p spec for broadcast. So their TV is compatible with a mythical nonexistant signal? Maybe from aliens?
Well, with this phone call they simply fessed up: The TV doesn't support 1080p at all. Apparently the "p" in their 1080p means "Pixels", the screen physically has 1920x1080 pixels, but lacks any hardware to properly process a 1080progressive signal. I had the guy & his supervisor tell me repeatedly "The TV will take a 1080p signal, but cannot display it" which really makes no sense. After about 10 minutes of trying to get him to explain how it can "take" the signal but not display it, he finally admitted most you can get out of this TV is 1080i.