If you have a look at the fuselages of Brabazon and XC-99, note that the outside fuselage width of Brabazon - about 500 cm - matches the width of Boeing 767 - 503 cm. Both have a single passenger deck. The fuselage length of Brabazon and XC-99 are both about 55 m, so roughly matching 767-300.
From
http://www.air-and-space.com/peacemkr/c ... sitive.htmwe can see the fuselage cross-section of XC-99. Narrower than Brabazon, at 434 cm outside, but still much wider than A320 (395 cm), and a doubledecker.
And here
http://www.air-and-space.com/peacemkr/c ... 9%20cl.jpgare a lounge and a restroom of a Pan Am Convair. 767 certainly does have space for such things... has anyone seen such features on any widebody jet?
So... a Princess is also a doubledecker. Does anyone know its fuselage width?