Buying jeans has been the bane of my existence for all of my adult life. You have NO idea. Seriously. It’s the same problem we all (on this site) have: big thighs and glutes, small waist.
I will literally spend an hour in a store that has every imaginable brand of jean you can conceive of, from your lame-looking Wranglers and Lees to all the hippest, priciest, coolest-looking jeans there are (PRPS, Sevens, Lucky, Chip & Pepper, etc.), and will try on 15 or so pairs in slow succession, with ZERO success. I’ll start out by explaining my situation to a (hopefully hot :)) sales girl and asking her what the absolute roomiest, loosest-in-the-thigh jeans they have are, aside from silly looking B-ball, hanging off your ass jeans. She’ll suggest one or two of the more hip, designer brands that she knows to be looser and she’ll dig out the most “relaxed” fit of those brands in my size.
I will try them on. Not even close. Probably won’t come past the mid-thigh level, or might, but then crush my twig and berries all the way to the inside of my ass, never to be seen again. Like the damn things are spray-painted on.
Next, I will try those same brands (if they were anywhere near having a prayer of fitting) in a size that’s one size too big. (I wear a 34 waist, so I’ll try them in 36, figuring I can get the waist taken in if need be). No dice. Either the thighs/ass are still way too tight, or the waist and hip area is SO loose that even having it taken in wouldn’t look remotely right.
I will repeat this two-step process about 6 to 8 times, bringing 2 to 3 pairs into the dressing room with me each time. I will feel bad for the cute sales girl, who is really spending serious time with me and trying hard to help me out. She will sometimes stand outside the dressing room after handing me another pair to try on and and will ask, after a minute or two, “How do those fit?” I will reply “Like a Japanese condom,” and hand them back to her. She will pause for a second or two and then let out an embarrassed laugh, realizing what I meant by that.
By this point I will be tired, frustrated, hungry, back and forehead dripping with sweat from the lack of ventilation in the dressing room, having stabbed one or both of my feet at least once with the invisible pins hidden in the carpet of the dressing room, hungry, longing for food and caffeine, pissed off, and will be openly cursing the pansy-assed “designers” who designed jeans that only some emaciated, heroin-addicted, pussy of amibiguous sexuality could or would ever wear.
I will thank the sales girl for all the time she spent out with me and I will leave, on a quest for food, coffee, and possibly a shower, planning to possibly return in 3 to 4 months time when the next season’s wonderful offerings have hit the store shelves, hoping that the pendulum of what’s “in” in the designers’ minds will have by then swung back to a more “relaxed” jean fit as opposed to a spray-painted on look.
Talk about a massive pain in the tits.
For the record, about 2 years ago I bout a pair of COOL AS SHIT looking PRPS (Japanese brand, about $250) that were nice and loose in the thighs, fit well in the waist, had an awesomely cool, semi-beat-up look to them, nice darkish blue but faded nicely in places . . . and I’ve loved them ever since. Since then, even PRPS has gone to a fit that makes their loosest models waaaay to skinny for me to get into. Hopefully that will change again soon.
Mavi jeans (whatever their loosest model is) tend to fit me just fine but they just look super-boring/plain to me. Hey, I’m in New York – we try to do it with style. 
Unfortunately, I have no advice for you. 