If I was planning to spend a staggering £15,000 on a TV (gawd knows how much it is in USD), I'd certainly go for the BV9 over and above the BV7-55. The picture isn't going to be any better than the BV7-40 and, indeed, could be worse (SD upscaled), has the same picture engine, same sound, same everything - just a 15" bigger screen for 50%+ more cash!
I'm in no way defending the 50% difference, but the screens are not the same.
XL: 55” 1920 x 1080 (Full HD), 16:9 TFT LCD direct-type LED backlight , local dimming, scanning backlight, glare surface
(from B&O web page)
Is B & O using a Samsung panel in the BV7-55?
The reason I ask is that,as far as I am aware,Samsung's 2009 LED TVs embody edge lit LED arrays,and do not feature local dimming.