It might be a stretch to say that ALL pornstars tattoos are bad, but I can't think of any good one's off the top of my head.
I think that I can pretty much say that there are no good lowerback tattoos, because I've never seen one. I guess the logic behind this is that only the kind of people that get bad tattoos get lower back tattoos, and if anyone had a good idea for one, they declined to get it because they realize that no one would take them seriously.