Instead of each 3 seats have a 6 foot bedbox stacked (upto four high, or more)with a width similar to that of current seats. These would replace all seats on the plane.
Pros: Built into the aircraft fuselage it would make it more rigid (like a honeycomb) and probably lighter in weight too, better in the event of fire, each box would be more isolatable ensuring better survivability. For the passenger it would enable one to get to sleep being in a reclined possition – hence more comfortable on long journeys. Each cubicle (bedbox) would have direct access to an aisle maybe by climbing down the boxes used as a ladder.Other considerations such as video screens could be built into the ceiling of each bedbox.