1080i/720p HD is HD no matter what. If you say YUCK to a 65" HD RPTV set then you were watching a ridiculously cheap, or horribly calibrated TV or one that had a serious internal malfunction, or all of the above. I have a 65" UltraVison HD RPTV and a 106" HD FPTV, both with absolutely perfect HD images.
Because at least @ 42" or more and I have a true theater like experience (which is what HD is supposed to be about) not sitting in the upper deck, bring the binoculars or squint experience.
I say why would anyone cheapen their HD experience by buying a set so small no one could tell or care less if it really was HD or not? This is almost as bad as people spending $5000 or more on a 40" flat panel TV just so they can tell their buddies they have a "flat panel" HDTV. They just overpaid by double or more for far less size HD than the same 1080i/720p in the other formats.
IMHO