Welcome to a fellow pear! I have similar coat fit issues, and like you, tend to go for classic, a-line shapes. I do find that most of the cocoon styles overwhelm me, because I have a rounded and proportionally smaller shoulder line. I tend to need something with defined shoulder seams, not the dropped or rounded shoulders found on most cocoon styles.
The swing coat, as mentioned above, is also an option. Depending on the style, it can somewhat mimic a cocoon coat.
You might want to try the Ellen Tracy Kimono coat pictured below. It's kind of a hybrid of swing and cocoon, and it fit me pretty well and I didn't even have to size up for hips like I usually do. (I didn't get it because I didn't love the colors, but I'm still considering it. It was nice and warm!). It comes in slightly different versions from different retailers (the finds are for the Lord and Taylor and Nordies' versions respectively). The one I'm trying in the photo is the L&T one.
One trick you might consider is that if a coat fits everywhere except at the hip button, which pulls because it is too tight, you can often move that button over an inch or so. It does depend on the cut of the coat, but I often find this solves the problem. I wouldn't try it if the coat actually won't button there, because it's likely that you won't be able to get enough room even with moving the button in that case.
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