Laura,
I seem to remember you don't do your weight workouts with Cathe. What weight are you using for squats/deadlifts/lunges.
My butt looked the absolute best when I was doing The Firm's "Standing Legs" with the sit and stands and floor work of Leaner Legs. It's that hover over the box that gets ya. Do you do step ups? Specifically, I prefer sit and stands over one legged step up-step downs... I would hold 15-30# dumbells while doing the sit and stands...?? Slow and Heavy is great, IMO, too.
Just a thought. Again, I have no clue what you are doing now.
But I have great genetics when it comes to the booty. Even when I don't do anything, I still have a "great butt" by most people's standards. It is just very high and rock hard when I lift alot. I empathize with you how frustrating that must be to work so hard and get so little return. And I certainly emphasize with the thicker thighs, for sure!!!