I would suggest that the reason you don't see bed rolls on the back of a Chally is because the only time that one got taken out was at night when they had their transponders turned off. The crew were sleeping on the rear deck totally unaware that one of their kind had spotted them, decided that they must be enemy, and fired at them!
It might be rather cramped inside that turret, hardly room to stand or sit anywhere, apart from on top of the charge bins, so my guess is that anyone suffering from insomnia goes straight to the top of the tank crew recruitment short list.
Very nice Abrams, it changes the lines of the tank completely when it has stowage all over it.
