Ridden with a passenger a few times.
Closest was with a girl while I was buzzed with about a month of riding in. Dumb I know but I did it. Anyways, she just caught my buddy tagging another girl and came to me pissed off. She use ot have a BF who rode and rode on the back so she knew how to be a proper bitch. I ended up hauling some ass on the bike which was easy now to me but probably to my limit then. She has her own bike now. A street fighter at that. And neither of us have a death wish (Or as big of one) anymore.
I've ridden in a 350z to 160mph as a passenger.
One buddy of mine who was outright squid and crazier to hell (Infact here is a video of him)
http://www.youtube.com/watch?v=a_vMhyaZwU0
I remember looking at his myspace page and seeing a girl write "It was fun riding the motorcycle. But next time we need to go faster". I saw him ride with a girl before (Infact the one I gave a ride to) and he rode like that with her on it (She was into stunting and stuff). So whoever that chick was had to be crazier than fuck.