Well, that's how her ass got big. She was in a ladies mag that my missus brought the other day, the photoshop guy had messed it up though, and by increasing her ass size, had mis-proportioned her thumb into some kind of RSI arthritic looking thing. Hideous. Anyway.... Brands, really, I think you're best to go I to your local shop and try some stuff on and see what fits bes, but you've already said that you've done that. Special blend, burton, roxy, ride, volcom, four square, sessions etc are all good brands that might fit. Just remember that your usually have a t-shirt or something on that will hide the top of the pants if you have to get them a size larger than your waist to fit other areas, and they end up having to be scrunched up.
Failing them not fitting properly, you could always buy some Lycra racing pants