I don't wish to detract from the reports here but a lot of the times are easily achievable in certain popular planes. A TB20 for example will stay up for >10hrs, probably nearer to 11, at 45% power, LOP, which is about 110kt ias. Even at 65% power, 140kt or so, it will go for 7:30 hours.
The need to pee is very easily addressed with the plastic bottle thingy from Transair etc. It just isn't wise to have a drink in the hour or two before takeoff, or a coffee in the preceeding few hours. To stay fresh, eat strawberries when up there
