Being somewhat small of waist and large of rear I have struggled for years to find jeans that don't gape at the waist. I finally found some in TK Maxx
They are straight leg jeans and are Saltworksbrand and are 77% cotton, 22% polyester and 1% elastane. I know that sounds horrible, but they are a perfect fit on me - my waist is 12" smaller than my hips. I have washed them already and they haven't shrunk, so I am feeling mighty pleased with myself.