Gerry Davis has adjustable waist pants. They are a very nice pair of pants and can move up or down a size. That means you can get a great fit during the fasts of Ramadan or right after eating Thanksgiving dinner. I have a pair and I really like them...although the clinicians at a particular camp I went to didn't as they have a sliding clasp on the waist on both hips to make the adjustment.
Edit: I just received this email from Gerry Davis, what a coincidence (I am in no way affiliated with Gerry Davis - heck I don't even know who he is!)
http://www.gerrydavis.com/mm5/catego.../H08PH12827300