Yes, on the QV and QE there is a passage way off from the casino area on 2 deck but you would never know as it is really quiet. Just nine cabins, but located there you are perfectly located for the theatre, casino, Queens Room etc.
On the QM2 they are mid ships but slightly more on decks two and three. I count fifteen on the deck plans. The ones on 3 deck (like in the photos) are wider than they are deep, as they occupy the space of the former photo gallery (I believe it was that) on 3L Deck, if you recall the Art Gallery on the other side of the ship which is very long, the same sized space is shared four six cabins so quite generous.
I've not tried one on 2 deck yet on the QM2, does anyone have any photos yet?