Which you can already do. This is exactly what business class is, right now! For example, the top deck of a BA 747 is entirely lay-flat business seats, which ar

Which you can already do. This is exactly what business class is, right now! For example, the top deck of a BA 747 is entirely lay-flat business seats, which are incredibly comfortable for long haul. But, as you say, you have to pay (somewhat) extra, or live in hope that the computer gods decide to upgrade you...