I've got to imagine that's true Sean - frankly moving my uncles was a pain in the ass too - those two paned ones had to weigh 200 lbs - versus the single panes these days that might push 60-70. (I'm not that strong and I can move my 51" solo - the difficulty comes from getting a good handhold - the weight doesn't wind me once I'm going... and I'm a scrawny guy...). Unless they reduced the weight per glass panel substantially it's likely easy to figure out by checking package weights on plasmas - <100 are likely one panel, >100 are likely two. [At least in my experience - as stated above the early plasma I'm familiar with was first consumer generation, when they were $7k or something ridiculous like that for 720p]
And yea, on buzzing the only time I can hear it for mine is if I pull mine away from the wall, like when I've got the TV sitting backwards - certainly has a buzz, but it's from the rear of the unit and projects that way, so from the front it's basically nonexistent, if someone gets a buzz they can notice I bet wall-mounting or otherwise reducing the distance to the wall would remove it from being detectable. (Or the buzz is coming from elsewhere, like shitty speakers on the unit that have a buzz)
