The one on Dime is 1.28gb and should be an edit of the transport stream itself.
This one is 1.54gb!
It's always possible that someone has done an high bitrate mpeg2 re-encode of it...
Either way, the one on Dime was uploaded at my request from the guy who said he'd upload last weeks Alice Cooper concert in HD (which he did earlier today). That one will be from the UK broadcast with huge gold MTVHD logo in the top right.
I have another one from the US broadcast which has a much smaller MTVHD logo in the top left in white, but that one is only the songs (again missing UP) and is 675mb in size for 1080p: probably an edit of the transport stream itself.
What the one in this thread is remains to be seen!