I'm a bit surprised that after your post, nobody even commented..... a really great demo vid you did there, and you taught me something...... I had no clue the 7D did NOT change aspect ratio...
I have the same monitor as you ( bought from Cool LCD . com ) and use it with m Canon T2i ( 550D ) and it DOES change aspect ratio to 4:3, and it drives me nuts.
Funn that the more expensive Canon also does this, yet the 7D doesn't. - Funny in a way when you think about it.
Great video, and thanks for posting !