Non-pilot speaking
bzh
In our company it's ok to have a rest in the flight deck, simple rules, one pilot at the time, advise the back end and schedule a call no more than 45min after being advise just in case the second pilot dosed off. and wake up at least 20min before TOD
That sounds like common sense. Which means that very few companies will do it. I have often read that cat-napping is meant to be a good way to lengthen life, by restoring you in the middle of your 'day'.