There is a great article that talks about the Bose Acoustimass system and compares it to audiophile grade components. (I can't seem to find it currently) The cubes are made of plastic, with nothing in them but air. The cubes are crossed over at around 280 Hz and the sub stops at about 200Hz or so. They actually remove some of the music. Appartently they feel this range of music is not important.
Most the large, elaborate displays have as much as 30K in electronics driving them. The need to get decent sound out of their displays. Ask the demo guy next time you are at the outlet to see the back room, to get a quick peek at the electronics. I'll bet he won't let you see it. THis is mostly in their outlet stores if I'm not mistaking.
As far as the CC and BB displays, who listens to their rear speakers inches from their head as the display emulates? Put the same setup in a room that is 13x20 and things start to fall apart like a cheap meatloaf.