Aft cabin centreline beds in an aft cockpit boat are for me a disaster on a sub 40'er. That is on every boat I've seen. Look great on the plans but the reality is that you are lying in bed with the cockpit floor right over the top of you. In a lot of them you can barely roll over let alone try and get down and dirty. As for sitting up in bed to read, forget it.
Based purely on my observations, maybe there are exceptions to the rule.
“Give a man a fire and he's warm for a day, but set fire to him and he's warm for the rest of his life.” Terry Pratchett