Well, I don't see it listed here, so here's my super-efficient and easy 3x1 room design:
+---+---+
|...|...|
+---+---D---+
|...|XXX|...|
+---D---+---+
|...|...|
+---+---+
+|- = Wall
. = Floor
X = Up/Down Stairs
D = Door
One "unit" = 6 rooms, 2 doors, 3 stairwells, fits within a 13x7 space (including walls), with an interior area = 39.
This takes advantage of the fact that a door on the corner of multiple rooms can open into each room. So, one door per three rooms. This means making 2/3rds less doors. If you put the bed right next to the door, then any sleeping dwarf is only two steps away from heading up or down to their workshop.
These units can be stacked on top of each other, or they can be tiled like this:
+---+---+
|...|...|
+---+---+---+---D---+
|...|...|...|XXX|...|
+---+---D---+---D---+---+---+
|...|XXX|...|...|...|...|...|
+---D---+---+---+---+---D---+
|...|...|...|...|...|XXX|...|
+---+---+---D---+---D---+---+
|...|XXX|...|...|...|
+---D---+---+---+---+
|...|...|
+---+---+
The triple up/down stairs means less crowding on the stairs, but you could use one or two sets of stairs instead, possibly even rotating leaving one out if you're worried about falling dwarves.
This pattern can easily be achieved by marking a whole area to be dug out, then unmarking every other horizontal line and every fourth vertical line (or vice-versa), then just adding in the doors and stairs.
Place this directly above or below the workshops of the dwarves that will be residing in them, with enough Z-levels to avoid noise if you feel like it, and the residents can quickly get back and forth between working and sleeping.
All in all, it's easy for you to make, requires less materials, maximizes available space, and minimizes travel distance for the dwarves.
I did come up with a slightly more efficient design than that:
+---+---+
|...|...|
+-+-+-D---+
|...|X|...|
+---D-+-+-+
|...|...|
+---+---+
One "unit" = 6 rooms, 2 doors, 1 stairwell, fits within a 11x7 space (including walls), so the interior area = 37, a mere ~5% improvement, but with more crowded stairwells. Also, harder to lay out and tile:
+---+---+
|...|...|
+---+---+-+-+-D---+
|...|...|...|X|...|
+-+-+-D---+---D-+-+-+-+---+
|...|X|...|...|...|...|...|
+---D-+-+-+-+-+-+-+-+-D---+
|...|...|...|...|...|X|...|
+---+-+-+-+-D---+---D-+-+-+
|...|X|...|...|...|
+---D-+-+-+---+---+
|...|...|
+---+---+
So, that's the most efficient bedroom design I can come up with, without putting stairwells or ramps into the bedrooms and with the privacy of a door. I prefer the first design over this one though.