Working for Virgin Atlantic way back when, I was very impressed by the romper rooms on the 744...at least on Virgin aircraft, you would find it in the back by the lav's. One of the doors opened to a semi-spiral staircase with ten bunks or so. Very cool...

I was not so impressed with the A340 (300/600), where the rest quarters were aircraft-center down in the belly. Don't know if there is any truth to it either, but I heard that they are actually pods that can be taken out of the aircraft much like the baggage cans...