Oh yea? Try fitting your roll aboard in the overhead of F/C row 1 or 2. Not happening unless it is sideways.

But yes, the rest of the tube is the same diameter,.

So, where is this 2 million dollars savings... (doubtful)

Must be from the crappy, noisy, hot/cold cramped 3/4 707 cockpit design huh. Too bad pilot ergonomics come so low on some peoples priority list.